title: Predictors of adverse perinatal outcome in twins delivered at < 37 weeks.
abstract: OBJECTIVE
  Multiple gestations are at increased risk for prematurity as well as perinatal mortality and morbidity. The aim of this study was to identify the independent risk factors for adverse perinatal outcome in a large uniform population of twins delivered preterm.
  
  
  METHODS
  We accessed a cohort of twin gestations for the period 1990-2000 delivered at < 37.0 weeks gestation. Chorionicity was established by ultrasound assessment of the dividing membrane, neonatal gender and histologic examination of the placenta at birth. Adverse perinatal outcome was defined as stillbirth, neonatal death, or major neonatal complications. Statistical analysis used contingency tables, Student's t test, one-way ANOVA and logistic regression, with a two-tailed p < 0.05 considered significant.
  
  
  RESULTS
  A total of 356 twin gestations (712 twins) were included in the database, and 183 twins (25.7%) had adverse perinatal outcome. Logistic regression analysis demonstrated that gestational age at delivery (p < 0.001), premature rupture of membranes (PROM) (p = 0.004), birth weight discordance (p = 0.009), and 5-min Apgar scores (p = 0.001) were significant and independent predictors of adverse perinatal outcome, whereas monochorionicity and twin-twin transfusion syndrome were not.
  
  
  CONCLUSIONS
  Gestational age at delivery and birth weight discordance are the most important independent predictors of perinatal mortality or morbidity among preterm twins.
authors.affiliation: Department of Obstetrics and Gynaecology, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Vergani
authors.forename: Anna
authors.initials: A
authors.lastname: Locatelli
authors.forename: Marta
authors.initials: M
authors.lastname: Ratti
authors.forename: Antonietta
authors.initials: A
authors.lastname: Scian
authors.forename: Giulia
authors.initials: G
authors.lastname: Zangheri
authors.forename: John
authors.initials: J
authors.lastname: Pezzullo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ghidini
mesh_terms: D001034:Apgar Score; D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D012307:Risk Factors; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic