title: Neonatal outcomes of twin pregnancies delivered at late-preterm versus term gestation based on chorionicity and indication for delivery.
abstract: OBJECTIVE
  To investigate the neonatal outcomes of twin pregnancies delivered at late-preterm versus term gestation based on chorionicity and indication for delivery.
  
  
  METHODS
  This is a retrospective cohort study of women with twin pregnancies delivered at ≥34 weeks of gestation from 1995 to 2014. Subjects were categorized into two groups according to gestational age at delivery: late-preterm group (34-36 weeks) and term group (≥37 weeks). Neonatal outcome measures including neonatal intensive care unit (NICU) admission, mechanical ventilator support, and respiratory distress syndrome (RDS) were compared between the late-preterm and term group based on chorionicity (monochorionic or dichorionic) and delivery indication (elective or non-elective).
  
  
  RESULTS
  A total of 1198 twin pregnancies were included in the study: 679 in the late-preterm group and 519 in the term group. Late-preterm twin infants had higher rates of NICU admission, mechanical ventilator support, and RDS than did term twin infants, regardless of the chorionicity and indication for delivery. In the multivariable analysis, late-preterm birth, monochorionicity, and non-elective delivery were independently associated with a significantly higher risk of NICU admission and mechanical ventilator support.
  
  
  CONCLUSIONS
  The late-preterm birth was associated with a higher risk of adverse neonatal outcome regardless of chorionicity and indication for delivery, and showed significantly increased risk by monochorionicity and non-elective delivery.
authors.forename: Ji-Hee
authors.initials: JH
authors.lastname: Sung
authors.forename: Soo Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Yoo-Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Ji-Hye
authors.initials: JH
authors.lastname: Kim
authors.forename: Mi-Na
authors.initials: MN
authors.lastname: Kim
authors.forename: Hye Ran
authors.initials: HR
authors.lastname: Lee
authors.forename: Hye-Jung
authors.initials: HJ
authors.lastname: Lee
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Suk-Joo
authors.initials: SJ
authors.lastname: Choi
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Oh
authors.forename: Cheong-Rae
authors.initials: CR
authors.lastname: Roh
authors.forename: Jong-Hwa
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000328:Adult; D002823:Chorion / Q000033:anatomy & histology; D015331:Cohort Studies; D036861:Delivery, Obstetric; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D059285:Pregnancy, Twin; D047928:Premature Birth / Q000453:epidemiology; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic