Perinatal Outcome of Vaginally Delivered Twin Gestations With a Larger Twin B

Abstract

OBJECTIVE: To study the perinatal outcome of vaginally delivered twins when twin B is more than 250 g larger than twin A.

STUDY DESIGN: Maternal and neonatal charts of live-born, nonanomalous twins, >25 weeks’ gestation and vaginally delivered over a period of 17 years were reviewed. The results of this review were distributed among two groups: (1) those with twin B more than 250 g larger than twin A (ΔBW>250) and (2) those where the difference was <250 g (ΔBW<250). For vaginally delivered twin gestations, the perinatal outcome of twin B in the group ΔBW>250 was compared to that of its co-twin, and to that of twin B in the group ΔBW<250.

RESULTS: Of the 679 twin gestations reviewed, 138 (20.6%) were in the group ΔBW>250, of whom 73 (52.9%) delivered vaginally despite malpresentation in 39.7%. The vaginally delivered twin pregnancies in the groups ΔBW>250 (n=73) and ΔBW<250 (n=303) had similar demographics, parity, presentation, gestational age at delivery, and duration of the first stage of labor. Discordant twins were more frequent in the group ΔBW>250 (26.0 versus 9.5%, p=0.001). Twin B in the group ΔBW<250 was smaller, with higher incidence of growth restriction, low 5 min Apgar score, and hyperbilirubinemia compared to twin B in the group ΔBW>250. There was no difference in the incidence of intraventricular hemorrhage, seizures, sepsis, neonatal death, and median nursery stay. Except for a lower median Apgar score at 1 min in twin B and a longer median nursery stay in twin A, twins A and B in the group ΔBW>250 were similar regarding all other neonatal outcome variables.

CONCLUSIONS:When twin B is more than 250 g larger than A, and both are delivered vaginally, the perinatal outcome is similar to its co-twin as well as to that of twin B of all other vaginally delivered twins. That twin B is larger than A is not itself a contraindication to attempted vaginal delivery.