The smart way to learn. The smart way to teach.

MRCOG PART 2 SBAs and EMQs

Course PAID
notes336
EMQ1502
SBA2115
Do you realy want to delete this discussion?
Forum >>

ESSAY 276 - NTD

Posted by Shachi M.
Shachi
(a) How will you determine her risk of having another baby with a neural tube defect? [4 marks]


The patient’s risk is determined with help of her personal & family history and screening tests.
A personal or family history of having a baby with neural tube defect (NTD) increases the patient’s risk of having an affected baby. A patient who is known to have epilepsy has higher risk of having congenital malformations (including NTD) and this risk goes up if the patient is on antiepileptic medication, more so if she is on polytherapy. Diabetes mellitus, malabsorption syndromes (celiac disease) and inflammatory bowel diseases (crohn’s and ulcerative colitis) are also risk factors for having a baby affected by NTD. A high level of maternal serum alphafetoprotein at 16-18 weeks of pregnancy means that the baby has a higher risk of having neural tube defect.

(b) How can the risk of neural tube defect be minimised? [3 marks]

The risk of NTD can be minimised by using folate fortified foods, taking periconceptual folate (400mcg) by low risk women and high dose (5mg once daily) folate in the periconceptual period by high risk women (previous history of affected baby, women who have epilepsy, diabetes and bowel disorders). Folate supplementation can be stopped after 12 weeks of gestation. In women with diabetes, a good glycaemic control reduces the risk of having a baby affected by NTD. Preconceptual counselling and patient education is instrumental in achieving compliance.
(c) Critically evaluate the screening tests for neural tube defects [6 marks].

Triple test is done between 16 to 18 weeks of gestation check for maternal serum alphafetoprotein, unconjugated estriol and beta-human chorionic gonadotrophin. It is a screening test for Down’s syndrome as well as neural tube defects. Alphafetoprotien is raised in open neural tube defects and hence this test will miss fetuses with closed neural tube defects. It has sensitivity of 66% and a false positive rate of 5%. It is a simple test which is widely available and acceptable to most patients. If the test comes back as high risk then further test like anomaly ultrasound scan is available. It is done between 18 to 20 weeks of gestation. It is a non-invasive test which is able to detect more than 95% fetuses with spina bifida. If a major neural tube defect is detected then termination of pregnancy can be offered to the parents.

(d) She subsequently becomes pregnant, has negative screening tests for neural tube defects but the baby is found to have spina-bifida at delivery. Justify your management. [7 marks]

This is a very distressing situation for the parents and should be handled in a very sensitive manner. The defect could range from mild abnormality with no long-term implications to baby’s health, to a severe one. The diagnosis should be explained to the patient and her partner. It should be explained to the patient that it is not her fault and there is nothing that she could have done that caused the baby to have NTD
The baby should be reviewed urgently by the neonatalogist to assess the extent and type of defect, to explain the prognosis and long term health implications of the abnormality, and to explain the treatment options available (if needed).
An incident form should be filled so that the process of the screening tests can be reviewed. However one should keep in mind that a screening test only gives a risk of the baby being affected and does not diagnose the condition.
Counselling should be offered to the parents and written information of support groups given.
A consultant appointment should be arranged to see the patient in 6 weeks to discuss the plans for future pregnancy.
Posted by Srivas  P.
(a) NTD have multifactorial etiology. Her risks are increased from 1:1000 in general population to 3-5% as she has had a baby with NTD. This risk is compounded if she has other risk factors also. Either parent having had NTD’s increases risk to 4%. It is difficult to assess combined risk in such cases. Risks of NTD is increased if she has uncontrolled diabetes, has IBD or is epileptic taking antiepileptic drugs. It ranges from 3% with single drug to almost 20% with 4 drug antiepileptic therapies. NTD’s maybe associated with Trisomy 21, 13, 18 and the risk of repeat NTD’s may be similar to risk of recurrences of these trisomies. In genetic syndromes like Meckel Gruber syndrome, recurrence risk could be even 25%. Excessive intake of VitaminA, and deficiencies of folic acid and Vit B12 increase risk.

(b) Prophylactic folic acid 400µg daily preconception and in first trimester in all pregnancies can decrease the risk and in high risk cases, she should be advised to take 5mg folic acid for same duration. Proper control of Diabetes by keeping HbA1C levels < 10% preconception and in first trimester and planning pregnancy during control can reduce risk . In woman with Epilepsy decreasing the drugs from multitherapy to monotherapy in liaison with neurologist can reduce the risks and pregnancy should be planned accordingly. Avoid excessive Vitamin A intake and products like Liver which contain them during first trimester.

(c ) Screening tests used are MSAFP levels between 15-20weeks, USG and amniocentesis.
MSAFP levels can be used initially to screen for high risk cases, to be followed by more sensitive tests like ultrasonography, but it has low sensitivity and specificity for NTD’s. The interpretation requires correct dating and the levels are lower in diabetic and obese patients and is raised in multiple pregnancy, IUD, fetomaternal haem making interpretation difficult. MSAFP is also raised in other conditions like abdominal wall defects, cong nephrosis, cystic hygroma, esophageal, duodenal atresia and some placental and umbilical cord tumors. It may also be nonspecifically raised in some pregnancies with no fetal abnormality detected. This test is also low in sensitivity-some 1% anencephaly, 10-15% spinal NTD and almost 50%encephaloceles are skin covered and do not leak AFP.
USG is more sensitive and it can detect anencephaly even in first trimester and detects 100% of anencephaly by 20 weeks but detects only 92-95% of spinal defects and may miss small defects. USG is operator dependent and needs experienced personnel and good resolution.
Amniocentesis has limited role in screening for NTD’s and is rarely used when MSAFP levels are raised but USG is negative.AF acetylcholine esterase is raised in NTDs and is faint in abdominal wall defects and negative in cong nephrosis. Amniocentesis is invasive procedure and is associated with procedure related risk of 0.5% miscarriage above background risk and is usually rarely needed for this purpose.

(d) She and are partner are likely to be very distressed by this and would need sensitive handling and explanation that screening tests do not detect NTD’s 100%. The prognosis, extent of disability can only be ascertained after assessment by neonatologist, Paediatric neurologist and neurosurgeon. She should have consultations from perinatal social worker and psychologist for mental support.
90% of the babies survive long term but may have disabilities like lower limb paralysis, urinary and fecal incontinence and sometimes mental disabilities and low IQ. The extent of disability depends on size, length and location of the lesion and presence of brain matter in the sac. It is likely there is no microcephaly or hydrocephaly as these are usually detected by USG. Small encephaloceles can be closed without much residual disabilities. The baby needs to be under surveillance for developmental delay and development of hydrocephalous. Subsequent support depends on extent of disability and her GP should be given details of necessary follow up. She should be encouraged to go for screening for NTD’s in next pregnancy even though it was not detected this time as USG can detect NTD’s in 92-95%. MRI may detect some cases of NTD missed even by USG and this option should be explored. She should have details of support groups like scottish Spina bifida association. Incident report should be written about unsuspected fetal anomaly at birth.
Posted by Manoj M.
A 34 year old woman has been referred to the pre-conception clinic. Her first pregnancy was terminated at 20 weeks gestation because of a neural tube defect. (a) How will you determine her risk of having another baby with a neural tube defect? [4 marks] (b) How can the risk of neural tube defect be minimised? [3 marks] (c ) Critically evaluate the screening tests for neural tube defects [6 marks]. (d) She subsequently becomes pregnant, has negative screening tests for neural tube defects but the baby is found to have spina-bifida at delivery. Justify your management. [7 marks]

A) The risk of a subsequent neural tube defect depends upon various factors. Her past obstetric history and nature of the neural tube disorder needs to be considered. Details of an isolated disease or if it was associated with any other anomaly needs to be evaluated by going through her past notes. If isolated usually the recurrence is low. Presence of any medical disorders like diabetes mellitus needs to be evaluated as this could increase the risk of neural tube disorders. A detailed drug history needs to be taken as anti epileptics, anti folate medications can increase neural tube disorders. A personal or family history of neural tube disorders can increase a risk of having another baby with neural tube disorders.
B) Preconceptual folic acid is essential; as she has a previous significant history she needs to take 5mg upto 13 weeks of pregnancy. The dosage needs to be 5mg in the presence of diabetes or drug history, however if there are no risk factors a dosage 0.4mg can be taken. If the patient is a diabetic then good glycaemic control is essential. If the patient is on medications like anti epileptics, she should be reviewed with a view to reducing it to monotherapy (if on polytherapy) or discontinuing it with the advice of physician. However if unable to discontinue it for medical reasons she should be appropriately counselled.

C) A raised maternal serum alfafetoprotein levels can indicate an increased risk of neural tube disorder. However the sensitivity of this test in screening for NTD is controversial and it may not be raised in closed defects. Therefore if raised a detailed ultrasound is mandatory. The results of ultrasound screening are operator and equipment dependant. Very large open defects are usually detectable and there is associated polyhydramnios, but closed defects are easily missed. The patient needs to be counselled in detail before undertaking an ultrasound examination. A referral to a tertiary centre and Fetal medicine specialist input is necessary. Thirdly an Amniocentesis can be done to check he levels of alfafetoprotein that is raised in open NTD. However it is not raised in closed defects. It also carries a 1% risk of miscarriage.

D) It can be extremely shocking for the patient therefore she should be counselled in a sensitive manner by the senior obstetrician. It is important to call her family/ partner whilst giving this news. A senior paediatrician should be present to go through treatment options with the couple. The extent of the problem and the associated nature of complications like susceptibility to infections, physical handicap needs to be explained. Consent should be taken to screen the newborn for other diseases. Referral to tertiary centre for treatment is mandatory. Support group details must be given. An incident form must be done and this should be discussed in the risk management meeting to evaluate the tests.
Posted by Sam M.

a.Risk for future pregnancies depends on family history of NTD.she will be asked about NTD in family as one sibling if affected then risk is 1:25 and if 2 then 1:10.It also depends whether any of the parent had NTD which increases risk.Antiepileptic drugs increases the risk so the history of epilepsy and antiepileptic drus is important.she will be asked about history of uncontrolled IDDM .geographical variation is significant,3:1000 incidence in Scotland and Northern Ireland while 2:1000 is in England.It is important in which part of country she is living.

B.Prophylaxis preconceptually and in first 3 months of pregnancy with 4 microgram/day for general population and 5 mg perday for high risk group is recommended.Good glycemic control in IDDM is important.Single drug with minimum effective dose for anti epileptic drugs minimizes the risk and fit free for >2 years then after consultation and discussion with patient and physician drug therapy can be stopped but great care is required as fit can affect her general health and driving licence .

c.Screening is done on the basis of risk factors ,by MSAFP,by scan amniotic fluid levels of AFP and acetylecholinesterases.. Though on dating scan 60 to 70 % of anencephaly can be diagnosed but spina bifida can not be. so anencephaly diagnosed in first trimester help in timely and relatively safe termination of first trimester pregnancy. MSAFP are significant if levels are >2.5 MoM . In closed neural tube defects this could be misleading as then level might not be raised signicantly or level are raised in conditions like wrong dates , fetal ,cord and placental abnormalities other than NTD. With raised MSAFP it is advised to do a detailed anomaly scan which can diagnose 85 to 90 % of NTD but it depends on equipment resolution and expertise of operater.Still this is not 100% sensitive screening test .Amniotic fluid AFP and acetylecholinesterase levels are highly specific and sensitive in diagnosis but this is associated with preganancy loss of 1% more thanthe general population with amniocentesis,so should be reversed for very high risk cases. Presence of risk factors can screen a woman for diagnostic tests as CVS and amniocentesis to carry out karyptyping but procedure related pregnancy loss is significant and require more experienced and trained operator with high resolution machines and then lab testing of specimen took time .

d.This is a very distressing situation to her and she needs to be approached with sensitivity and sympathy .She will be explained about diagnosis and other finding or abnormalities found. Furthur management depends on neonate condition and type of anomaly .In presence of multiple anomalies or NTD as a part of syndrome survival will be less .she will be told that baby needs urgent referral to paediatric surgeon for consultation and chances of corrective surgery. This will be explained that despite of corrective surgery , bladder and bowel dysfunction and lower limb abnormalities could be there .Though etiology of NTD is multi factorial but with repeated NTD she needs genetic counselling .A follow up appointment with consultant be arranged for detailed debriefing and discussion about future pregnancies .Written information will be provided so that she can discuss with her partner about further pregnancies and contraception
Posted by g.b. D.
gb


a)
The patients risk is determined by various high risk factors in her history like presence of diabetes, epilepsy and chronic malabsorption syndrome. In these conditions folic acid deficiency if prevalent which predisposes to neural tube defects. The risk is increased with positive family history and syndromic association in the previous terminated baby.
With one previous sibling affected it is 4% and with one parent risk is 8% and with both it increases to around 12%.A combined risk has to be determined by maternal fetal medicine specialist and clinical geneticist.The risk can be determined by various screening tests like maternal serum alfa fetoprotein levels and ultrasound.


b)
The risk of neural tube defects can be minimized by periconception folic acid in dose of 0.4 mg in low risk cases and 4 mg/day in high risk cases from 3 months preconception till 12 weeks of pregnancy.in cases of epileptics on antiepileptic medication it should be continued till term.
The risk can also be minimized by good control of blood sugars in diabetics .In epileptics converting polytherapy to monotherapy and in lowest possible dose in consultation with neurologist decreases the risk. In cases of malabsorption syndromes parenteral folic acid will reduce the risk.

c)
Screeing tests for neural tube defects include maternal serum testing for alfa feto protein (MSAFP)levels and use of ultrasound scan.
MSAFP levels are done at 16 –18 weeks as a part of triple test. The levels will be raised in open neural tube defects. It has a sensitivity of 72% for open spinal defects and 88% for anencephaly with a false positive rate of 0.01% . It is simple test involves a blood sample to be sent to lab. However it is not sensitive for closed defects.
The levels are also raised in various other conditions like abdominal wall defects, preterm labour , preeclampsia or gastrointestinal abnormalities like oesophagial atresias. Hence it is not specific test. It needs accurate estimaltion of gestation age by an early dating scan by ultrasound. The levels are not reliable in multiple gestation, obesity and diabetes and experienced person is needed for interpretation of MOM values.

Ultrasound has a sensitivity of 100% in detection of anencephaly and it can be done as early as 10-11 weeks where an early termination of pregnancy can be offered to the patient. It has a sensitivity of 92% for spina bifida false positive rate of 0.003% .However relies on a few indirect findings like lemon sign and banana sign and may miss smaller defects.It needs a trained operator to detect anomalies. The advantage is when done at 18-20 weeks it can detect other causes of raised alfa feto protein at the same screeing.It is non invasive tool.

d)
It is natural for the patient to be shocked and angry and demand explaination for the missed diagnosis. However it is important to handle the situation in a calm and empathetic way. It is important to provide honest explainations regarding the protocols in such situations. It should be highlighted that the screeing tests have limitations and are not 100% diagnostic. When there is no doubt on screeing tests the patients are not subjected to more invasive tests like amniocentesis which involve procedure related risks including pregnancy loss. It is important to provide adequate support from the staff till they come to terms with the diagnosis. She should be offered a followup a later date for any more concerns.
The baby should be reviewed by neurologist and neurosurgeon to determine the extent of defect and need for further intervention. A meeting of couple with these specialist has to be arranged with the couple to give idea of extent of defect,the further action and care required and the outcome of interventions.
The contact numbers of support groups should be provided.
A risk management form has to be filled to look in to the defects in screeing protocols.
Adequate contraception should be provided. The need for preconception folic acid emphasized and a plan for next pregnancy formulated with seniors and communicated to her at the followup visit.









Posted by Asma kamal K.
(a)Her risk will be determined with a detail history. I will take a detail obstetric history, number of past pregnancies(if appropriate), previous pregnancies out come, other than the termination at 20 weeks were there any other children affected by neural tube defect(NTD). As one affected pregnancy increases 2-5% risk of NTD and two affected pregnancies increases it to 10%. If any one /both of the parents are affected by NTD then the risk of having an affected pregnancy is 1-5%. Maternal insulin dependent diabeties mellitus (IDDM) also increases the risk. Antiepileptic drugs therapy , maternal gastric bypass surgery and certain ethenic groups are at higher risk(Irish and Scotts). A positive family history (even in 3rd degree relatives) also increases the risk .
(b)Risk can be minimized with 5mg folic acid supplementation 12 weeks before and 12 weeks after contception. Good glycemic control (in diabetics) pre and post-conception. Mono drug therapy in epileptics if possible . No anti epileptic drug is superior then other in reducing the risk for NTD. Early Screening for the NTD will decrease the incidence of NTD defect at birth with termination of affected pregnancy but will not decrease the incidence.
(c) Patient personal and family history is good screening tool to identify at risk population and appropriate steps can be taken to minimize the risk of occurrence of the NTD and to triage high risk woman for further screening tests. This will dcrease the work load and will be cost effective. Maternal serum alfa feto protein(MSAFP) levels can be measured around 16-18 weeks. Which will show raised levels (with respect to gestational age) in pregnancy with NTD. MSAFP are however unreliable in multiple pregnancies. It needs accurate dating of the pregnancy and levels are affected by maternal weight(low level with higher BMI) and IDDM(low levels).Raised MSAFP is not exclusively seen in NTD but are also associated with maternal smoking ,male gender, miscarriage, IUD, upper GI obstruction, Congenital nephrosis and obstructive nephropathy. MSAFP may not be raised in covered NTD, hence if only serum screening is used such defects can be missed. NICE guidelines recommend that where Tertiary level ultrasound scan examination can be done serum screening need not be done USS is more cost effective. USS can detect 99% of anencephaly and 90% of spinabifida , along with that it is more reliable in multiple pregnancy, IDDM and obese. USS can detect other associated abnormalities and can locate the site and can estimate the extent of the defect as well. USS can exclude other causes for raised MAFP levels. Tertiary level USS needs expertise and high resolution machine which have cost implications and require regular training. In a high risk patient like this patient if no abnormality is detected on USS but MSAFP levels are high then amniocentesis can be offered to detect amniotic fluid AFP and acetyl cholinesterase levels. Amniocentesis is invasive test with 1% pregnancy loss rate. In patient with open NTD karyotyping should be offerred.
(d) Delivering a baby with spinabifida with negative screening tests is a great psychological trauma. The may show extreme anger and may demand explanation. A sensitive, sympathetic and empathic approach is needed .Patient and her partner will be told that screening test does not detect the anomaly 100% and an invasive test (with its own inherent pregnancy loss risk) only offered if strongly suggested by the screening test. The abnormality will be explained to them in easy language, its implication and management options explained. It may be a small NTD correctable surgically with no residual sequalae or it may be a big and complex NTD requiring extensive surgery and may lead to lower limb paraplegia, urinary and bowel sphincter dysfunction. Spina bifida with associated ventricular abnormalities may lead to learning and neurological impairment. Idealy they should be counseled by a multidisplinary team comprising of Obstetrician, neonatologist, neurosugoen,psychologist,midwife, and NICU nurse. Psychological support will be provided. Contact numbers of the relevant support group and of those who are bringing up children with NTD will be given. Adequate contraception and preconception 5mg folic acid will be advised.A date for follow up visit with consultant obstetriacn will be given to allow her to discuss her concerns. The incident will be reported(form filled) to improve the health care facilities.
Posted by San S.
(a) How will you determine her risk of having another baby with a neural tube defect? [4 marks]
First of all, I would like to know if she has pre-existing medical conditions that put her at risk of having a baby with neural tube defects e.g. epilepsy, diabetes. It is important to assess the nature, severity and if these conditions are well-controlled.
Medications that are folate antagonists could increase her risk of neural tube defects e.g.antiepileptics and the risk of neural tube defects is dose and type of antiepileptics dependant.
It is also important to establish if she has any family history of the conditions or other genetic disorders which predispose her at higher risk. If there is no other risk factors, and this being an isolated event, the risk of recurrence is low.

(b) How can the risk of neural tube defect be minimised? [3 marks]
I f she has existing medical disorders e.g. diabetes and epilepsy, these should be well-controlled prior to pregnancy. Modification of treatment if she is a known elpileptic on treatment may be considered e.g. stopping treatment, using monotherapy and lowest dose possible to control the disorder.
In view of previous TOP due to neural tube defects, I would offer her high dose folate 5mg once daily prior to conception and at least throughout 1st trimester.

(c ) Critically evaluate the screening tests for neural tube defects [6 marks)
A good screening test are those with high sensitivity and low false positive rate hence avoid unnecessary invasive interventions. Maternal serum screening at 16-18 weeks gestation (double, triple or quadraple tests) has different sensitivity (ranging from about 70- 85%) and false positive rate (ranging form about3-6%) depending on numbers of serum markers used for the test i.e double test having the lowest sensitivity and highest false positive rate compared to quadruple test. The test available for a particular unit is dependant on the funding available for the screening test.
Anomaly scan at 20 weeks gestation has higher sensitivity and less false positive rate than maternal serum screening but this is operator dependant and can be an expensive source of screening. In some unit, this method of screening has substituted maternal serum screening.

(d) She subsequently becomes pregnant, has negative screening tests for neural tube defects but the baby is found to have spina-bifida at delivery. Justify your management. [7 marks]
I would explain the diagnosis to her and her partner in a sympathetic manner and she should be reviewed by a senior obstetrician as well. Review by a senior neonatalogist and paediatric surgeon should be arranged as soon as possible to discuss investigations for other structural abnormalities, available corrective surgery and possible prognosis of the baby.
Clinical incident form should be filled in for undiagnosed congenital abnormalities and the case should be registered with the national congenital abnormalies register.
It is important to liase with community midwife and GP with her management as she may need social and psychological input in the community. An out-patient follow-up should be arranged for debriefing and as an opportunity to review her well-being and management for future pregnancy to prevent recurrence.
Posted by A P.
A.The recurrence risk with a previously affected child is 1 in 25. However, there are several risk factors involved which could increase this risk and a thorough history needs to be taken. This may reveal a family history of neural tube defects. For example two affected siblings produces a 1 in 10 risk. An autosomal recessive condition e.g. Meckel-Gruber will increase the risk. The patient should be asked about previous use of folic acid as she is likely to require a higher dose. Review of the autopsy report is important for counselling as possible associated karyotypic abnormality eg trisomy 18 is less likely to recur. A medical history of poorly-controlled diabetes mellitus, epilepsy or gastric bypass surgery are also risk factors requiring multidisciplinary input to optimise therapy pre-pregnancy. Thus, providing the patient an idea of the recurrence risk involves careful counselling and written information.
B.The risk of neural tube defects may be minimised by taking 0.4 mg folic acid per day or 5mg once daily (with past history of neural tube defects) 3 months before and during the first trimester. This is explained to the patient giving written information emphasising that folic acid does not eliminate the risk of a neural defect. Anticonvulsant drugs and poorly controlled diabetes or epilepsy may increase the risk of an affected child and treatment will require optimisation to reduce the risk of neural tube defects.
C. The main screening test is alpha-fetoprotein (AFP) taken by blood. It has a sensitivity of 76% for a 5% false positive rate when part of the quadruple test (age, AFP, human chorionic gonadptrophin, unconjugated estriol). Screening programmes for neural tube defects rely on estimation of maternal serum AFP. Optimal screening is between 16 and 18 weeks The results are expressed as multiples of the median (MOM) allowing different laboratories to interpret the results in a common manner. Hence, an AFP of at least 2 MOM detects 100% of anencephaly and 80% of open spina bifida A unit protocol is required for their interpretation. Open defects will produce a raised AFP. However, a closed defect may reveal a normal result. A screening test merely gives an idea of high or low risk: it is not diagnostic and the patient must be counselled carefully. Written information is given including contact details for availability and discussion of results. The diagnostic test following positive screening is ultrasound which detects 100% and 98% of fetuses with anencephaly and open spina bifida respectively.
D. This is a distressing situation for parents and requires sensitive and careful counselling. Spina bifida has a spectrum of presentations. Management will commence with review of the screening tests and documentation of the information given during antenatal counselling and interpretation of the results. Discussion with the patient involves ascertaining her understanding of ‘negative’ tests for neural tube defects. The type of spina bifida seen at delivery is significant since a closed lesion has a skin covering, is usually small and not seen via ultrasound. Hence, alpha-fetoprotein (AFP) levels are not raised and may not be detected on serum screening. However, if the lesion at delivery is an open spina bifida, this may have been missed on ultrasound or more rarely AFP was incorrectly interpreted as normal. These are likely to be risk management issues necessitating completion of an incident form and informing the consultant. Other explanations include limitations on imaging especially if obese. In addition, not following the unit protocol for screening, inadequately trained staff or inappropriate machinery would necessitate further training and audit. The patient is given a further opportunity to re-address any issues preferably with a consultant.

Posted by Manoj M.
A 34 year old woman has been referred to the pre-conception clinic. Her first pregnancy was terminated at 20 weeks gestation because of a neural tube defect. (a) How will you determine her risk of having another baby with a neural tube defect? [4 marks] (b) How can the risk of neural tube defect be minimised? [3 marks] (c ) Critically evaluate the screening tests for neural tube defects [6 marks]. (d) She subsequently becomes pregnant, has negative screening tests for neural tube defects but the baby is found to have spina-bifida at delivery. Justify your management. [7 marks]

(a) She has a recurrance risk of 5% for future pregnancies affected by neural tube defect (NTD) as her first pregnancy was affected by NTD.
If either of her or her partner is affected by NTD this will also increase the risk in future pregnancies affected by NTD.
If she is affected by epilepsy and on anti-epileptic drugs (AED) like sodium valproate, carbamazepine, phenytoin which causes folate deficiencies may increase her risk for having babies affected by NTD, other folate deficiencies states like malabsoption syndromes, inflammatory diseases will also increase her risk for pregnancies affected with NTD.
If she is affected by diabetes and conception with uncontrolled diabets (HBA1c >10%) will increase her risk of having babies affected by NTD.
Obesity is also associated with increased risk of pregnancies with NTD.

(b) Risk of neural tube defect can be minimised with folic acid supplementation of 5mg daily orally, ideally starting 3 months preconception and continue through pregnancy untill atleast 12 weeks of pregnancy, this will minimised folate deficiencies. A high dose folic acid is advisable because of high risk for NTD with previous pregnancy affected by NTD.
If diabetic good glycaemic control (HBA1c<8%) will reduce the risk of NTD.
Reducing Body mass index in Obese individual with exercise and dititian input can also minimise the risk of NTD.
Epeleptic patients should be managed with specialist input from neurologist for good seizure control with lowest possible dose of AED, ideally with monotherapy and switch from medications like valproate and carbamzepine if possible only with neurologist input this should be done.

(c) Ultrasound scan(USS) in pregnancy is a very sensitive screening tool for detecting NTD.
USS can be used in the late first trimester (9-11+6 weeks) to detect NTD like anencephaly and spina bifida with very high sensitivity. It may needs trained specialist input to confirm diagnosis.
Second trimester(16-18 weeks) raised maternal serum alpha feto-protein (MSAFP) may suggest open neural tube defect which can be confirmed again with USS.
This may also need fetal medicine specialist input for accurate diagnosis of NTD which may have better prognosis and treatment options.
Second trimester amniotic fluid assay (14 weeks onwards) can suggest NTD with the ratio of alpha feto-protein and acetylcholine esterase but carries the extra risk of 1% procedural related fetal loss and not routinely practised as detection rate with USS is good for open NTD.

(d) This should be dealt very sensitively ideally with a special appointment with the consultant obstetritian and consultant paediatritian together.
she should be explained the limitations of antenatal screening tools not able to detect all NTD.
Most of spina bifida babies do fine with no problems with normal quality of life.
Those affected with spinal cord involvement may be subjected to surgical treatment with input from paediatric surgical teams which can improve the quality of life.
Those babies affected with neurological compromise and bladder problem have limited treatment options and support groups like associations for spinabifida and hydrocephalus (ASBAH) are available.
Breast feeding is safe for the baby.
Explanation for appropriate contraception untill planning for future pregnancy.
Recommendation for folic acid preconception for future pregnancies.
Options for prenatal diagnosis for future pregnancies.
Posted by J P.
a.The risk of having another baby with neural tube defect can be estimated by careful ellicitation of history. Personal history of neural tube defect increases the subsequent risk by 2-5%.Family history of neural tube defects also increases the risk.Previous obstetric history of a baby having neural tube defect increases the recurrence risk by 1-5%.History of epilepsy and the use of antiepileptics [mono or poly therapy] increases the risk further.History of diabetes mellitus wll be carefully enquired which increases the risk.Careful drug history like methotrexate, which interfere with folic acid metabolism also increases the background risk.Any history of surgery like gastric by pass surgery which interfere with folate metabolism and the risk of subsequent neural tube defect will be determined.

b.The risk can be minimized by folic acid administration 5mg periconceptually and continuing to 12 weeks antenatally.Strict glycemic control by adequate diet and insulin can reduce the risk but not eliminate the risk.Drugs used in epilepsy if polytherapy can be converted to monotherapy to minimize the risk.

c.Screening tests for NTD include USG pelvis and maternal serum alpha fetal protein.Estimation of maternal serum alpha feto protein is done by 16-18 weeks.The levels are expressed as MoM and has to be adjusted in obesity and multiple pregnancy.Accurate gestational age by dating is essential for calculation of risk Maternal serum alpha fetal protein may also be raised in conditions other than NTD like wrong gestational age, congenital nephrosis,abdominal wall defects, chronic feto maternal haemorrhage. If levels are raised after adjusting to gestational age, Ultrasound abdomen and pelvis is done to detect neural tube defects.About 99% of anencephaly and 95% of spina bida can be detected by USG by detection of lemon or banana signs. It is non invasive.But Ultrasound interpretation is operator dependent ,needs skill,maintenance of equipment and may miss small defects.
I f ultrasound is normal in presence of raised MSAFP ,amniotic fluid alphafeto protein and acetyl cholinesterase will be estimated.The risk is of the invasive procedure amniocentesis and the risk of fetal loss is 0.5-1%.Moreover 10-15% of NTD are covered by skin and do not leak alpha feto protein.Adequate post test counseling will be done.
c.This comes to as a shock to the parents and attenders.The initial reaction of anger and the emotional reactions should be handled with utmost care. I will explain the nature of condition and the prognosis will depend on the nature of condition which will be further discussed in conjuction with paediatric surgeon.I will explain that there may be situations where in closed NTD MSAFP will be normal and ultrasound abdomen might have missed small defects. If it is a lethal anomaly and subsequently baby dies consent for karyotyping and detecting any other anomalies will be done.If the baby survives explain that longterm neurological sequelae like bladder instability and lower limb
weakness cannot be predicted at birth.Support groups addresses will be provided and advice regarding contraception will be made.
Posted by Vaishali Sriniv J.
a)I will ask her history of neural tube defect in her first or second degree relative as it is associated with increase risk of neural tube defect. I will enquire about h/o insulin dependant diabetes . I will ask her if she is taking any medication such as antiepileptic drugs, as it is associated with increased risk of neural tube defect. I will inform her that in her first pregnancy fetus had neural tube defect so there is 3 to 5 % risk of developing neural tube defect in subsequent pregnancy.
b)She should be started on folic acid tablets 5 mg once a day. She should be told that folic acid tablets taken around conception and continued up to 12 weeks reduce the incidence of neural tube defect. If patient is having insulin dependent diabetes then she should be advised to achieve appropriate glycemic before conception. She should be told that it would reduce the risk of neural tube defect. If patient is taking antiepileptic drugs she should be informed that the risk is same with all drugs and taking folic acid along with medication will reduce the risk. She is to report early after she conceives as she will need screening for neural tube defects. In diabetic or epileptic patients, if control is not adequate then she should be given advice about contraception. . If level is raised then she will be offered ultrssound scan to detect the defect
c)Patient can be offered biochemical or ultrasound screening. The biochemical screening includes measurement of maternal serum alpha feto protein level between 16 to 20 weeks.The serum level more than 2.5 times of MoM for that gestation indicates increased risk. . If level is raised then she will be offered ultrssound scan to detect the defect The sensitivity of the test is about 72% .Being biochemical test there is no inter observer error. But the alpha feto protein level may be low in many conditions like diabetes, obese patients or overestimation of gestational age so they should be interpreted correctly.In defects covered by skin the level may not be raised. Ultrasound examination is noninvasive but expertise is required. In major defects like anencephaly diagnosis is possible in late first trimester. So early diagnosis may enable early termination. Other defects like spina bifida or encephalocele can be diagnosed at the time of anomaly scan. The sensitivity of ultrasound in diagnosing anencephaly is around 99% and in other defects is about 90 to 92%. The closed defect may be missed.
d) Patient will naturally feel distressed and angry. It is important to approach her in sympathetic way. Baby should be examined by the neonatologist to determine the extent of lesion. Patient and her partner are to be explained about the diagnosis and its long term implications. The baby may have small defect with little affection to large defect causing paralysis. Baby should be referred to tertiary centre for evaluation by neurosurgeon and the patient should be told about options available and the prognosis Her records should be checked and results of screening reviewed and incident form filled.Patient should be told that screening tests are not diagnostic and there are limitations to the tests.. Patient should be informed that as first two pregnancies were having neural tube defects the risk of affection is up to 10% in next pregnancy. She should be given appointment for genetic counseling. Advice about contraception is to be given.
Posted by SHAGUFTA T.
A) A detailed history, examination & certain investigations will help in determining her risk of getting other affected pregnancy with Neural tube defect. As she had her first pregnancy affected by Neural tube defect (NTD), she has risk of recurrence by 2-5 % in this pregnancy. If she or her partner is affected by NTD, there is another 1-5% increase in risk of getting NTD. A detailed family history of any 1st, 2nd, or 3rd degree relative affected with NTD will be taken as this is also a risk factor. I will also take her detailed obstetric history—if this is her 2nd pregnancy or she had any other pregnancy in between & its outcome. As if 2 or more siblings are affected with NTD the risk increases to 10%. I will enquire about her ethnicity as Scotts & Irish population have high incidence. A detailed medical history will be elicited as IDDM especially uncontrolled & inflammatory bowel disease will be at increased risk. If she is epileptic and on Antiepileptic drug will increase the risk of NTD. Her past surgical history is also important as gastric bypass surgery also increases the risk. Investigations like HBA1C, drug levels of antiepileptics might help.
B) She has high risk of recurrence in next pregnancy which can be minimized by giving high dose of Folic acid 5mg orally from 12wks preconception to 12wks of gestation. If she has IDDM, good glycemic control prepregnancy will reduce the risk. If she is epileptic on multidrug therapy, conversion to monodrug therapy with lowest possible dose should be considered in conjunction with Neurologist. Early screening & prenatal testing to detect NTD & offer termination of pregnancy will reduce the incidence at birth. Written information leaflet will be provided to avoid risk factors & guidance for proper diet & folic acid.
C) Risk determination/ calculation of having affected baby by personal history, Medical & surgical history & strongly positive family history is one method of screening, it can detect the woman at increased risk, cost effective and indicate need for further screening & testing. But this cannot predict the risk precisely or detect NTD. MSAFP done at 16-18 wks is accurate screening test, non invasive, objective, operator independent but needs accurate dating of pregnancy by early dating scan. MSAFP can be raised in multiple pregnancy, wrong dates, male fetus, maternofetal hemorrhage, congenital anomalies & many other conditions. It can be low with Trisomy 21, 18, IDDM, obese mother. Second trimester anomaly scan at 20-22wks is best diagnostic test. It can detect 99-100% anencephaly & 92-95% Spina bifida by lemon & banana signs. It can detect the site of defect & other congenital anomalies like cardiac defects. However needs operator expertise & costly advanced USS machine but still can miss 5-8% of spina bifida. Invasive testing by Amniocentesis to detect amniotic fluid AFP & acetylcholinesterase is only indicated if MSAFP is abnormal with normal scan but it cannot detect these in amniotic fluid if defect is closed type. And Amniocentesis has its inherent risk of 1% pregnancy loss, infection, preterm labour, method failure. This also need thorough Pre & post test counseling. According to NICE guideline if detailed anomaly scan is done at tertiary centre AFP is not needed.
Delivery of 2nd baby with NTD despite negative screening will put the parents in acute stress, anxiety, emotional upset & anger. Dealing with them empathetically is of paramount importance. Multidisciplinary team involving Consultant obstetrician, Neonatologist, Pediatric surgeon & counselor is needed to explain the finding and assess the baby’s general condition, extent of defect & future need for surgery & prognosis. They will be informed that not all NTDs can be detected antenatally. After detailed examination of neonate by senior neonatologist & pediatric surgeon, the prognosis will be explained. If small defect with mild neurological deficit, can have better prognosis with corrective surgery if needed. With major defect and Neurological deficit like paraplegia or bowel/bladder sphincteric involvement may need major surgery & even then poor outcome. Information leaflet regarding sequele of NTD & prevention in future pregnancy provided. Details of Spina bifida support group & those upbringing children with NTD will be given. Followup appointment arranged, future need of contraception discussed. Preconception counseling in next pregnancy explained. Incident form for risk management will be filled & clearly documented.
Posted by H P.
H
(a) Preconceptionally her risk is determined by her personal, family and medical history. Her history of previous baby with neural tube defect (NTD) increases risk to 3-5% as compared to 0.1% in general population.
History of NTD in the family, even in her sister’s child increases the risk by 2-5%. If either partner is known to have NTD then the risk increases to 4%.
I will check her medical history for IDDM, epilepsy or gastric bypass surgery. Uncontrolled IDDM increases the risk for NTD.
All anti-epileptic drugs increase the risk by 4-5% if on monotherapy. The risk increases upto 15-20% if on three or more anti-epileptic drugs.
I will check her previous obstetric notes and findings for the previous baby. If the previous baby had syndromic cause for NTD like Trisomy 13 or 21, the risk for recurrence is the same as that for the aneuploidies. In case of Meckel-Gruber syndrome, the recurrence risk is 25%.

(b)
Preconceptional folic acid for atleast 12 weeks is proven to reduce the risk for NTD. An oral dose of 400mcg/ day in the low risk population and 4mg/day is recommended for high risk cases like a previous baby with NTD, insulin dependent diabetics, epileptics on medication and personal/ family history of NTD. Counselling and patient education play a central role.
Strict glycaemic control for IDDM is very important.
In case of epilepsy, changing polytherapy to monotherapy in liaison with neurologist will reduce the risk.
Parenteral folic acid may need to be given to patients with gastric bypass surgery or malabsorption syndromes.
(c) Raised MSAFP (maternal serum alpha fetoprotein) levels of more than 2.5 MoM at 16-18 weeks have a sensitivity of 70% for open spinal defect and 88% for anencephaly. It is a simple test involving a blood sample. However, it is dependent on accurate dating of gestation and values are not reliable in maternal obesity (low), DM (low) or multiple pregnancy (high). Many other conditions also raise MSAFP levels like Trisomy 21, abdominal wall defects, preeclampsia, congenital nephrosis or gastrointestinal abnormalities. So need to follow up with detailed scan. Also, closed NTD may not raise level.
Ultrasound (USG) is a non-invasive tool. USG at 10-11 weeks will pick up about 80-85% of anencephaly and by 16-18 weeks 100% of anencephaly and 80-85% of open spinal defects can be picked up. It can also pick up other signs for NTD like lemon/ banana sign. Also, as it detects at earlier gestation, termination can be offered earlier.
It can also detect other causes of raised MSAFP. But is highly operator dependent and needs proper equipment. Small or closed defects may be missed. However, it is cost-effective and where available, there is no need for MSAFP screening.
Amniotic fluid acetyl-cholinesterase is highly specific for open NTD but involves invasive testing. Amniocentesis has 1% risk of fetal loss over and above the general risk. It is useful in presence of raised MSAFP with normal USG findings.

(d)
At delivery, if the defect is open, will need to be covered under sterile drapes and immediate referral is made to the neonatologist and paediatric neurosurgeon.
She and her partner may be extremely distressed and need empathetic counselling by senior obstetrician.
The type and extent of the defect and any neurological impairment needs to be assessed. After appropriate consent, baby should be screened for other associated structural anomalies. A meeting should be arranged with both partners involving the obstetrician, neonatologist, neurologist and paediatric neurosurgeon to explain the findings and long term prognosis of the baby.
She should be told that screening methods only give the risk for a condition. She should be given information of support groups like Association for Spina Bifida and Hydrocephalus.
Her GP should be informed of the findings and she may need psychological support.
A postnatal review is arranged in 6 weeks time to discuss her concerns and plan for future pregnancy with consultant obstetrician. Contraceptive counselling is given and need for preconceptional folic acid emphasized.
Incident form is filled for undiagnosed congenital anomaly and review of available screening tools . The case is registered in the National Registry for congenital anomalies.


Posted by Farina A.
a)previous hostory of NTD increases the risk by ten fold. besides that thhe pt should b easked about and screened for diabetes. history of epilepsy and anti epileptic drugs, like carbamazipine and and na valproate are important to determinethe risk of NTD.Various malabssorption syndromes preventing absorbtion of vitamin B12 and folic acid like pernicious anemia, chrons disease and ulcerative colitis can contribute in development of NTD.
b)Risk can be minimised by adequate glycemic control, avoidence of pregnancy in epileptics needing high doses and repeated fits, avoidance of polytherapy in well controlled subjects and fo;ic acid supliments of 0.4mg in low risk cases while 5mg in high risk cases. Food can be fortified with folic acd in a population with a staple diet poor in folic acid.Relevant bowel diseases should be treated in collaboration with gastroenterologists.
c)matternal serun alpha-fetoprotiens are high in NTD however one can find higher levels in wrong dates, threatend miscarriage, twin pregnancies and Downs syndrome. This test increases matternal anxiety due to its low specificity. Amniotic fluid acetylcholine easterase levrels can be high in open neural tube defects . US can detect upto 92% of cases of spina bifida hoeveer the factors effecting the sensitivity of US are operator experience. matternal habitus( thick abdominal wall), amount of liqour and quality of equipment.
d)the case should be dealt sensitively and careless expressions about prenatal diagnosis should be avoided. Patient should be reassured that there is nothing on part of her responsible for the condition.Patient should be told about the difference between screening and diagnostic tests, that screening test can only identify the risk. The baby should be examined thoroughly in the presence of a senior paediatrician and the extent of the lesion and disabily is determined. senior obstetician and paediatrician should counsel the woman and her partner about the sensitivity of the screening tests and the prognosis of the malformation. the woman should be provided with written information and contacts of support groups and paediatric rehabilitation centres. An incident form should be filled and the relevant department (radiology) involved in the screening tests should be informed. The baby can be reffered to the higher centres for appropriate management and rehabilitation.
Posted by SK K.
A> To determine the risk of having NTD, I would ask for history of total number of affected and unaffected pregnancies and children, presence of the defect in herself or her husband , the presence of medical illness eg: IDDM, intake of medication causing folate antagonism eg: antiepileptics .The presence of any of the above increases the risk of NTD. Also as she had a pregnancy affected previously their is a recurrence risk of 1-5 %.

B) mainstay in minimizing risk is supplementation of folic acid. Usually a dose of 400 ucg starting before conception and continued upto 12- 14 weeksof gestation is recommended. But as she is at high risk of recurrence and if she has risk factors, like being on antiepileptics drugs, she should be started on 5 mg folic acid instead of 400 mcg. Other measures like fortification of food flour with folic acid, optimizing of blood sugars if she is diabetic , will also minimize the risk.

C) Screening test for neural tube defects include MSAFP, USS. MSafp done at 16-18 weeks has a sensitivity of 79% with false positive rate of 0.001%. however this aids in screening for open NTD & not closed, hence chances of missing a closed spina bifida.
Also there are a number of conditions in which MSAFP is unreliable eg: multiple pregnancy, fetus with abdominal wall defect, preeclampsia, maternal smoking, IDDM, wt. of mother.
USS has a sensitivity of 81% for false positive rate of 0.003%. It can distinguish between open and closed spina bifida. Lemon sign, banana sign , Arnold chiari malformations are known association of spina bifida, detectable by USS .
USS is non invasive and reliable, reproducible, however it requires skilled personal & expertise .

d) the neonate needs to be examined in detailed. It is imperative to note if it is open or closed spina bifida, asses length & extent of defect, extent of severity as may lead to paralysis of limbs. Also necessary to note if there are associated anomalies.
USS should be arranged to look for evidence of neural tissue in the meningeal sac as this would indicate poorer prognosis.
Karyotyping should be offered if indicated.
The couple should be informed of the anomaly in a sensitive manner.
Parents need to be told that though the screening tests were negative the test have there own limitations and are not 100 % effective in detection .
Also they should be made aware of any associated anomalies and likely prognosis. Involve multisdiscipplinary ca re and arrange meeting with neonatologist, pediatric surgeon. Explain to them the nature of surgery, timing of undertaking surgery, success rates & risks of the surgery.
They also need to be informed of prolonged hospital stay and put into contact with support groups.

Accurate documentation & incident report form needs to be filled.
Posted by Drxyz A.
DRXYZ
a) Risk of having another baby with neural tube defect can be determined by taking personal and the family history of neural tube defect. If parent affected the risk of recurrence is 1 in 25. If one sibling affected again risk is 1 in 25. History of taking anti-convulsant drugs for epilepsy, history of diabetes, history of malabsorption syndrome as all of these conditions lead to increased risk of neural tube defect.
b) Risk of neural tube defect can be minimized by giving preconceptional folic acid 5 mg and continued till 12 weeks of pregnancy. Fortification of the food with folic acid can be done but has poor evidence of efficacy. Diabetes should be controlled preconceptionaly, Hba1c should be less than 10 and in epileptics polytherapy should be changed to monotherapy before conception. Alcohol should be avoided.
c) Screening of neural tube defect by detection of alpha feto protein. It will be high in open neural tube defects and can detect 80 to 90 percent cases of anencephaly and spina bifida but its interpretation is difficult in cases of multiple pregnancy, diabetes, mistaken dates, obese women, hypertensive patients and other congenital abnormalities like anterior abdominal wall defect, and congenital nephrosis. Other method of screening is Ultrasonography. It can detect 80 to 90 percent of the cases of spina bifida and anencephaly but depends upon the expertise of the sinologist.
d) couple should be approached with sympathy and they will be explained about the condition of the baby. As prognosis of the baby depend upon the site and type of lesion and associated neurological abnormalities so the paediatric neurosurgeon will be consulted for the management of the baby. An incident report will be written about the screening result as it was negative. Couple should be given information about support group
Posted by Atashi S.
a) As she has a H/O a baby with neural tube defect she is at risk of having baby with NTD of about 2 to 5 %. IF she or her husband has a H/O having NTD then she is at risk of having NTD of about 1 to 5%.If she has insulin dependant diabetes mellitus and has no good glycaemic control then she is at risk of having NTD affected baby .If she has epilepsy and on antiepileptic therapy , she is at risk of having baby with NTD .Use of polytherapy increase the risk. H/O gastric bypass surgery is also a risk factor.

(b ) Prophylactic folic acid therapy for three month in the preconceptional period and up to 12week after conception can reduce the risk . Good glycaemic control in case of IDDM will reduce the risk. If she is on antiepileptic polytherapy then it should be changed into monotherapy.
(c) Maternal serum alpha feto protein level is a screening method. Most accurate at 16 to18 week gestation. But raised MSAFP is associated with several condition including wrong date , multiple pregnancy , abdominal wall defect ,upper GI tract obstruction ,congenital nephritis , placental and cord tumour ,sacrococcygeal teratoma, maternal liver disease all of those need to be excluded .USG is an screening tool. Increase nuchal translucency at 11to 13 week gestation is suspicious. It also increase in down syndrome, cardiac anomaly. Details anomaly scan at 16 to 18 week detect 92% of spinabifida and 100% of anencephaly. Amniotic fluid alpha fetoprotin and acetyl cholinesterase should be measured if MSAFP is abnormal but USG reveals no abnormality. There are some debate between serum screening and USG as the more cost effective modality. NICE guideline suggest when USG is available, alpha fetoprotein is not required.

(d) It is a very critical situation to the clinician as well as to the patient. This case should be managed in a sensitive way. Psychological support should be given to the patient and to her husband .Proper explanation of the condition is to be given. Screening test not always exclude the condition that should be properly explained. Paediatric surgeon and paediatric neurologist should be urgently called for examination of the baby and proper explanation should be given to the parents regarding extent of the defect as well as which type of treatment required. A risk management form should be filled up. Written information and leaflet on NTD should be provided to the parents. Contact details of support group should be given.
Posted by Farkhanda A.
A—How will you determine her risk of having another baby with neural tube defect (NTD)
The NTD is a multifactorial condition and its risk can be determine by taking her history in detail as well as family history.The risk of NTD is 1.1000 in general population, but her risk of having a baby with NTD has increased by 2-5%, If parents or third generation relatives have NTD, then risk is 3-5%.
I will enquire about any medial disease like epilepsy, diabetes , Mal-absorption syndrome and inflammatory bowel disease(chrown disease and ulcerative colitis).I will enquire about any bowel surgery such as gastric by pass surgery, also increases her risk of NTD.
I will enquire if her epilepsy is well controlled or if she is taking antiepileptic. If she is on mono-therapy, then her risk will increase upto 4%, otherwise on poly-therapy this risk will be as high-as 20%. Her IBD should be well controlled before embarking pregnancy.
Diabetes increases risk of congenital malformations including NTD. Chromosomal defects such as trisomies 21,13 and 18 also associated with increase risk of NTD.
B---How risk of NTD can be minimised.
Risk of NTD can be minimised but cannot prevented. Every pregnant woman should be given folic acis 400ug daily from 12 weeks before achieving pregnancy and continue for first 12 weeks in pregnancy. In high risk such as this lady dose should be 5 mg daily for same duration. She should take folate fortified foods.
Before embarking pregnancy. Diabetes must be well controlled and especially during organogenesis period , that is, from 6-9 weeks of pregnancy. This can be monitored by checking HBAC1 which should be <10%.
Epileptic mother even with well controlled diseased has an increased risk of congenital malformation as compared to general population. This risk will increase if she is taking antiepileptic drugs. Before pregnancy, epilepsy should be well controlled, if not then better to take mono therapy rather than poly therapy.
C--- Critically evaluate screening tests for NTD
Screening tests for NTD are serum, Ultra sound scan USS and amniocentesis.
Serum screening test is usually offered in second trimester at 15 -17 weeks. It is called triple test. Mostly it is used as a screening test for Down syndrome, but we can see the level of AFP which is part of this test. In NED level of AFP is raised if it is open defect such as open spina Bifida or open encephalocele, But there are two limitations in this screening test. First 10 to 15 % cases are with closed spina Bifida which do not leak AFP and so test will be false negative. Second limitation is that AFP is raised in many other conditions such as abdominal wall defect, congenital nephrosis, Umbilical cord and placental tumour, threatened and missed miscarriage, intra uterine death and many conditions other than NTD.
USS has high sensitive and specificity in first and second trimester. It can pick 100% anencephaly and 92-95 % open spina Bifida, encephalocele. It may miss small defects.
Amniocentesis is not routinely performed for NTD diagnosis, but if AFP is raised and USS is normal, then it has some place. Before this invasive procedure good counselling is important including procedure related risk of miscarriage which is 0.5-1%.
In amniotic fluid level of acetyle -cholinesterase is checked which is increased in NTD, mildly increase in abdominal wall defect and nothing in congenital nephrosis.
D---All screening tests are negative, baby born with spina bifida, justify management.
This is very distressing situation. I will inform about the diagnosis to the mother and partner. It will be explained in a very sensitive way that this is not a fault of her or any other . It can be missed even after screening tests. Taking parents into confidence, I will involve neonatologist, paediatrics neuro surgeon who will do detail examination of the baby and discuss about the prognosis, timing of operation and residual long term effects on physical health such as
Pre-discharge counselling may contain risk of NTD in subsequent pregnancy, Contact details of support groups like Scottish spina Bifida association and an appointment with consultant in 6-8 weeks time. Incident form will be filled up for risk management as baby born with undiagnosed abnormality after all screening tests were negative.

Posted by hoping ..
A 34 year old woman has been referred to the pre-conception clinic. Her first pregnancy was terminated at 20 weeks gestation because of a neural tube defect. (a) How will you determine her risk of having another baby with a neural tube defect? [4 marks]
A) She is at high risk of having another baby with neural tube effect as she has had affected pregnancy. Details with regard to predisposing factors for folic acid deficiency for example intake of certain antileptics as carbamazepine should be obtained as folate deficiency is one of the common causes. If she is known diabetic or suggestive symptoms should be gathered as diabetes is associated with increased risk of neural tube defcts. If woman or her partner have evidence of neural tube defect as closed spina bifida may not have been diagnosed and is associated with increased risk of transmission to fetus. History of malabsorption syndromes and haemoglobinopathy also predisposes to folate deficiency causing neural tube defects.
(b) How can the risk of neural tube defect be minimised? [3 marks] She should be advised to take 5mg of folic acid from atleast 3 months preconception upto 12 weeks of pregnancy as this is effective in reducing recurrence in high risk pregnancies. If she is diabetic, her blood sugars should be stablised before conception as near normal HBA1C levels are associated with reduced risk of congenital anamolies. If she is on antifolate medication consideration should be given to discontinuing these aor changing to alternative drugs.

(c ) Critically evaluate the screening tests for neural tube defects [6 marks]. First trimester ultrasound may identify major neural tube defects like anencephaly with high sensitivity. Early identifiaction enables opportunity for termination if parents wish at earlier gestation and thus low risks to mother. Second trimester detailed fetal anamoly scan identifies more than 90% of these anamolies. This has better sensitivity for spina bifida and hydrocephalus compared with first trimester scan. This is best available screening test for neural tube detection and is non invasive. Biochemical test involves checking serum AFP levels but has lower detection rates as closed neural tube defects have normal AFP levels and AFP levels are affected by other factors like maternal weight , bleeding gatrointestinal anamolies.
(d) She subsequently becomes pregnant, has negative screening tests for neural tube defects but the baby is found to have spina-bifida at delivery. Justify your management. [7 marks]
This is unfortunate event and parents need to informed of diagnosis sensitively. They should be allowed to vent out their emotions and supported. Couple should be informed that screening tests are not diagnostic tests and unfortunately have false negatives. Paediatricians should be involved in counselling and discussion regarding prognosis and treatment options for baby. Morbidity depends upon level and extent of defect and child may have normal neurological development.Parents may have undiagnosed neural tube anamoly and thus investigations offered. Before discharge community midwife should be informed and regular mentalhealth assesments should be done as stressful pregnancy and peripartum period is associated with increased risk of postnatal depression . Parents should be provided with information and contact details of local and national supprotgroups. Recurrence risk in future pregnancy is likely to be high. Rarely parents may refuse to accept child , in that case measures should be taken to arrange for adoption of child.
Posted by Ephia Y.
A 34 year old woman has been referred to the pre-conception clinic. Her first pregnancy was terminated at 20 weeks gestation because of a neural tube defect.

(a) How will you determine her risk of having another baby with a neural tube defect? [4 marks]

Her risk due to one previous pregnancy with a neural tube defect (NTD) is 4-5%. If she or her partner has a NTD, the risk is about 5%. Diabetes mellitus especially with poor glycaemic control at the time of conception, epilepsy and anticonvulsant drugs especially polypharmacy increases risk. Risk is also increased if there is Coeliac disease or inflammatory bowel disease such as Crohn’s disease and ulcerative colitis due to poor absorption of folic acid.

(b) How can the risk of neural tube defect be minimised? [3 marks]

The risk of neural tube defect can be minimised by supplementation of folic acid in the dose of 5mg daily. Good diabetic control preconceptually and during conception will reduce risk of NTD. Risk is also reduced if single anticonsulvant is used as opposed to multiple drugs in epilepsy. Drugs such as Lamotrigine and Leviteracetam may have reduced risk.

(c ) Critically evaluate the screening tests for neural tube defects [6 marks].

Screening tests available for NTDs are biochemical screening and imaging.
Measurement of maternal serum alpha feto protein (MSAFP) at about 16-18 weeks is one screening test but it has low specificity as it can be elevated in other conditions such as upper GI obstruction and in not elevated in closed NTD. AFP can also be measured in amniotic fluid but it is invasive and carries 1% risk of miscarriage.
Good resolution ultrasound has a specificity of 95%. First trimester ultrasound can detect anencephaly and encephalocele but may miss spina bifida as signs such as ‘lemon’ sign and ‘banana’ signs are subtle or absent in the first trimester. Second trimester ultrasound is more sensitive and specific. 99% of anencephaly and 90% spina bifida are detected by ultrasound. With trained and experienced operators and good resolution ultrasound detection rates are close to 100%.
3D ultrasound and MRI can be useful if ultrasound is inconclusive but are seldom necessary.

(d) She subsequently becomes pregnant, has negative screening tests for neural tube defects but the baby is found to have spina-bifida at delivery. Justify your management. [7 marks].

The bad news of the presence of congenital anomaly is broken to the couple sensitively and empathetically. Counselling and psychological support offered. The nature of the anomaly is explained to the couple.
Multidisciplinary team approach to management is adopted with paediatricians, paediatric neurosurgeons and consultant obstetricians. The prognosis and treatment depends on the severity , level and extent of spina bifida. The risk of long term sequelae such as incontinence, paraplegia and intellectual impairement is explained.
The notes are checked to see if patient was on folic acid and the dose, any preconceptual advice and results of AFP if available and anatomy scan. The couple are informed that diagnosis may be missed in about 5% of cases.
An incident form is filled up due to a missed congenital anomaly.
The patient is offered written information and address and contact numbers of support groups.
The risk of NTD in a future pregnancy will be in the region of 10% due to two NTDs and pre pregnancy counselling is advised