D antibodies in pregnant women in multiethnic Suriname: the observational RheSuN study

Maternal antibodies against the D antigen are the most common cause of severe hemolytic disease of the fetus and newborn (HDFN). In high-income countries, the risk of D immunization has been reduced by routine antenatal and postpartum administration of RhIG from 13% to less than 0.5%. In less-resourced countries, such as Suriname, red blood cell (RBC) antibody screening during pregnancy and prophylactic RhIG administration are not routine. Accurate data on D immunization risk is not available. In the RheSuN (Rhesus Surinamese Neonates) study, the prevalence and the hemolytic potential of maternal D antibodies were investigated.

A multicenter cross-sectional study in four major hospitals in Paramaribo, Suriname, covering 90% of approximately 10,000 births yearly in Suriname. Included were D- pregnant women of various ethnicities seeking routine prenatal care and/or their newborns.

D antibodies were detected in 19 of 214 D- pregnancies (8.9%; 95% confidence interval, 5.1%-12.7%), in 2.0% of primigravid and 11.7% of multigravid women. The direct antiglobulin test was positive in 11 of 13 tested D+ newborns. Determination of D antibody titers and antibody-dependent cell mediated cytotoxicity (ADCC) assay revealed three newborns at high risk for HDFN (ADCC > 50%).

D immunization risk in Suriname women is comparable to the pre-anti-D prophylaxis era in high-income countries. Recommended is free-of-charge routine RBC antibody screening and prophylactic RhIG administration for women at risk for D antibody formation as part of standard of ante- and postnatal care.