A good answer should include
(a) Antenatal management
MDT care with fetal medicine centre and blood transfusion service
Assess risk of fetus being affected
· History of previous affected pregnancy
· Paternal Rhesus genotype – discuss limitations
· Fetal Rhesus genotype – based on amniocentesis. Discuss limitations
· Use cell-free DNA in maternal blood. Discuss limitations
Subsequent management dependent on fetal Rhesus type
· If fetus is Rh negative, reassure
· If fetus is Rh positive or status uncertain - serial quantification of level of anti-D antibodies. Fetal anaemia rare below 10-15 IU
· Monitor for fetal anaemia using serial middle cerebral artery Doppler (peak systolic velocity) every 1-2 weeks. High risk of anaemia if >1.5MoM
· Fetal blood sampling if evidence of anaemia on Doppler
· Intra-uterine transfusion if haematocrit < 30%
· Antenatal corticosteroids for fetal maturity
· Aim for delivery at 34-36 weeks if transfusion has been required or 37-38 weeks if no transfusion needed
· Antibodies may delay cross-match so blood gouped & saved if in labour / before CS
(b) Reasons for perinatal morbidity
· Allo-immunisation to other antigens (Rhesus E / c and other red cell antigens) for which prophylaxis is not available
· Missed prophylaxis – omitted / delayed in previous pregnancies
· Failed prophylaxis
· Occult feto-maternal haemorrhage
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