title: 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.
  
  
  METHODS
  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 (DeltaBW>250) and (2). those where the difference was <250 g (DeltaBW<250). For vaginally delivered twin gestations, the perinatal outcome of twin B in the group DeltaBW>250 was compared to that of its co-twin, and to that of twin B in the group DeltaBW<250.
  
  
  RESULTS
  Of the 679 twin gestations reviewed, 138 (20.6%) were in the group DeltaBW>250, of whom 73 (52.9%) delivered vaginally despite malpresentation in 39.7%. The vaginally delivered twin pregnancies in the groups DeltaBW>250 (n=73) and DeltaBW<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 DeltaBW>250 (26.0 versus 9.5%, p=0.001). Twin B in the group DeltaBW<250 was smaller, with higher incidence of growth restriction, low 5 min Apgar score, and hyperbilirubinemia compared to twin B in the group DeltaBW>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 DeltaBW>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.
authors.affiliation: Department of Obstetrics and Gynecology, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Ihab M
authors.initials: IM
authors.lastname: Usta
authors.forename: Anwar H
authors.initials: AH
authors.lastname: Nassar
authors.forename: Antoine A
authors.initials: AA
authors.lastname: Abu Musa
authors.forename: Johnny T
authors.initials: JT
authors.lastname: Awwad
authors.forename: Khalid A
authors.initials: KA
authors.lastname: Yunis
authors.forename: Muhieddine A-F
authors.initials: MA
authors.lastname: Seoud
mesh_terms: D000328:Adult; D001722:Birth Order; D001724:Birth Weight; D002657:Child Development / Q000502:physiology; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007746:Labor Presentation; D007744:Obstetric Labor Complications / Q000175:diagnosis; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple; D011336:Probability; D012189:Retrospective Studies; D014427:Twins