Outcome of severely anaemic fetuses treated by intrauterine transfusions

Background: Fetal anaemia is a well-known complication of pregnancy, which might have an ominous effect on the course of pregnancy, labour and the child's development. Objective: To assess the effect of the severity of fetal anaemia on the child's outcome. Methods: A retrospective cohort study. Pregnancies treated by intrauterine transfusions for fetal anaemia at Sheba Medical Center (1996-2004) were divided into two groups: mild to moderate anaemia (fetal haematocrit >0.50 multiples of the median (MoM)) and severe anaemia (hydrops fetalis or fetal haematocrit ≥0.50 MoM). Data were retrieved from relevant obstetric and fetal medicine files. Results: During the study period, 54 fetuses were treated by 154 (median 3; range 1-7) intrauterine transfusions for red cell alloimmunisation. The sensitising antigen was D in 70% of cases; 18/54 patients were sensitised to more than one antigen. Thirty-three of the 54 fetuses (61%) were in the severely anaemic category (haematocrit range 3-20%); six were hydropic. Twentyone of the 54 fetuses (39%) were in the mild-moderate anaemic category (haematocrit range 20-37%). On prenatal evaluation, there were no sonographic markers of central nervous system abnormalities or intraventricular haemorrhage. There were no differences in the neonatal outcome between the two groups. Developmental outcome was available in 14/18 (78%) mild-moderate cases and 26/29 (89%) severe cases. There were no significant differences in motor development score, percentage of abnormal cognitive development, and percentage of children needing supportive therapy between the mild-moderate and severe cases. Conclusion: Neonatal and developmental outcome of fetuses treated for severe anaemia is comparable to cases of mild anaemia.