FETAL HEMOGLOBIN CHANGES IN THE TWIN OLIGOHYDRAMNIOS-POLYHYDRAMNIOS SEQUENCE

Fetal hemoglobin concentration was measured in each twin from five mon ochorionic pregnancies complicated by twin-to-twin transfusion, diagno sed by growth discordance and coexistent oligohydramnios-polyhydramnio s. In three cases the hemoglobin concentration of the smaller twin wit h oligohydramnios was lower than the normal mean for gestation, and th e hemoglobin difference as more than 5 g/dl in two of these cases. In the other two cases, the hemoglobin concentration of the four fetuses with coexistent oligohydramnios-polyhydramnios was within the normal r ange. This suggests that twin-to-twin transfusion may occur without he moglobin changes, or that alternatively coexistent oligohydramnios-pol yhydramnios occurs in the absence of twin-to-twin transfusion.