title: Are women who have had a preterm twin delivery at greater risk of preterm birth in a subsequent singleton pregnancy?
abstract: OBJECTIVE
  The purpose of this study was to determine whether preterm birth of twins is associated with an increased risk of preterm birth in a subsequent singleton pregnancy.
  
  
  METHODS
  All patients who delivered a twin gestation and a subsequent singleton pregnancy at Northwestern Memorial Hospital during a 10-year period were identified. We used a cohort study design, comparing the outcomes of the singleton pregnancies in women with preterm twin deliveries to those pregnancies with term twin deliveries.
  
  
  RESULTS
  One hundred sixty-seven women delivered twins followed by a singleton pregnancy. Women whose twin delivery was preterm (n = 99) were more likely than those who had delivered a term twin pregnancy (n = 68) to deliver a subsequent preterm singleton pregnancy (13.1% vs 2.9%; odds ratio, 5.0; 95% CI, 1.1, 22.9).
  
  
  CONCLUSIONS
  Preterm birth of twins is associated with an increased risk of preterm delivery in a subsequent singleton pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. f-facco@md.northwestern.edu
authors.forename: Francesca L
authors.initials: FL
authors.lastname: Facco
authors.forename: Kate
authors.initials: K
authors.lastname: Nash
authors.forename: William A
authors.initials: WA
authors.lastname: Grobman
mesh_terms: D000328:Adult; D015331:Cohort Studies; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D007752:Obstetric Labor, Premature / Q000503:physiopathology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple / Q000502:physiology*; D047928:Premature Birth / Q000503:physiopathology*; D011379:Prognosis; D012306:Risk; D012307:Risk Factors; D014427:Twins / Q000502:physiology*