title: Amniotic fluid discordance in monochorionic diamniotic twin pregnancies is associated with increased risk for twin anemia-polycythemia sequence.
abstract: OBJECTIVE
  To estimate the risk for twin anemia-polycythemia sequence (TAPS) and adverse perinatal outcome in monochorionic diamniotic (MCDA) twin pregnancies with amniotic fluid discordance (AFD).
  
  
  METHODS
  Retrospective cohort study of 34 MCDA pregnancies with AFD (intertwin difference of ≥3 cm in maximal vertical pocket measurement) without meeting the criteria for twin to twin transfusion syndrome or selective intrauterine growth restriction. Perinatal outcome measures and the risk for TAPS were compared with a control group consisted of 101 MCDA twin pregnancies without AFD, twin to twin transfusion syndrome, or selective intrauterine growth restriction. Composite neonatal morbidity was defined as the presence of respiratory distress syndrome, intraventricular hemorrhage grades 3 and 4, necrotizing enterocolitis or sepsis.
  
  
  RESULTS
  Overall, in the AFD group, seven twin pairs (20.6%) were complicated by TAPS compared with none in the controls (p < 0.001). In the AFD group, women who developed TAPS had significantly higher AFD compared with women who did not develop TAPS (7.3 cm vs 4.2 cm, p < 0.01). Patients in the AFD group delivered earlier (34.6 vs 35.8 weeks, p < 0.001) and had significantly higher rate of composite neonatal morbidity compared with the control group (13.2 vs 2.5%, p = 0.002).
  
  
  CONCLUSIONS
  Despite the overall favorable outcome, MCDA twins with AFD are at increased risk for developing TAPS. © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Liran
authors.initials: L
authors.lastname: Hiersch
authors.affiliation: Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Mayan
authors.initials: M
authors.lastname: Eitan
authors.affiliation: Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Eran
authors.initials: E
authors.lastname: Ashwal
authors.affiliation: Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Boaz
authors.initials: B
authors.lastname: Weisz
authors.affiliation: Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Benny
authors.initials: B
authors.lastname: Chayen
authors.affiliation: Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Shlomo
authors.initials: S
authors.lastname: Lipitz
authors.affiliation: Department of Obstetrics and Gynecology, Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Yoav
authors.initials: Y
authors.lastname: Yinon
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000000981:diagnostic imaging; D016022:Case-Control Studies; D002543:Cerebral Hemorrhage / Q000453:epidemiology*; D020345:Enterocolitis, Necrotizing / Q000453:epidemiology*; D005260:Female; D005330:Fetofetal Transfusion / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D000071074:Neonatal Sepsis / Q000453:epidemiology*; D016104:Oligohydramnios / Q000000981:diagnostic imaging / Q000453:epidemiology*; D006831:Polyhydramnios / Q000000981:diagnostic imaging / Q000453:epidemiology*; D011247:Pregnancy; D059285:Pregnancy, Twin; D012127:Respiratory Distress Syndrome, Newborn / Q000453:epidemiology*; D012189:Retrospective Studies; D014430:Twins, Monozygotic; D016216:Ultrasonography, Prenatal