Postponing Early intrauterine Transfusion with Intravenous immunoglobulin Treatment; the PETIT study on severe hemolytic disease of the fetus and newborn

Background: Intrauterine transfusion for severe alloimmunization in pregnancy performed <20 weeks’ gestation is associated with a higher fetal death rate. Intravenous immunoglobulins may prevent hemolysis and could therefore be a noninvasive alternative for early transfusions. Objective: We evaluated whether maternal treatment with intravenous immunoglobulins defers the development of severe fetal anemia and its consequences in a retrospective cohort to which 12 fetal therapy centers contributed. Study Design: We included consecutive pregnancies of alloimmunized women with a history of severe hemolytic disease and by propensity analysis compared index pregnancies treated with intravenous immunoglobulins (n = 24) with pregnancies managed without intravenous immunoglobulins (n = 28). Results: In index pregnancies with intravenous immunoglobulin treatment, fetal anemia developed on average 15 days later compared to previous pregnancies (8% less often <20 weeks’ gestation). In pregnancies without intravenous immunoglobulin treatment anemia developed 9 days earlier compared to previous pregnancies (10% more <20 weeks), an adjusted 4-day between-group difference in favor of the immunoglobulin group (95% confidence interval, –10 to +18; P =.564). In the subcohort in which immunoglobulin treatment was started <13 weeks, anemia developed 25 days later and 31% less