Fetomaternal hemorrhage in monochorionic diamniotic twins at 37+ weeks' gestation: A rare complication.

Fetomaternal hemorrhage refers to a clinical syndrome in which fetal blood enters the maternal circulation through the placental villous spaces, typically triggered by specific stimuli, and may lead to fetal anemia or maternal hemolysis. The occurrence of fetomaternal hemorrhage is very rare in singleton pregnancies and even rarer in multiple gestations. In monochorionic diamniotic twin pregnancies, shared placental circulation can amplify the consequences of fetomaternal hemorrhage, potentially resulting in more severe outcomes than in singleton pregnancies or in twins with double chorions and double amniotic sacs. A 39-year-old woman, natural conception, gravida 3, para 1, monochorionic diamniotic twins, refused to terminate the pregnancy at 36 + 3 days. An emergency cesarean delivery was performed at 37 + 3 weeks because of a sinusoidal fetal heart rate pattern, with a decision-to-delivery interval of 27 min. Both neonates were born with severe neonatal asphyxia and anemia but demonstrated favorable recovery with resuscitation of neonatal asphyxia and transfusion therapy. Flow cytometric analysis of maternal blood revealed a fetal hemoglobin F fraction of 11.93%, confirming fetomaternal hemorrhage.