title: Mode of delivery and subsequent reproductive patterns. A national follow-up study.
abstract: OBJECTIVE
  To investigate associations between mode of delivery and subsequent reproductive outcomes.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Women with term singleton live births from 1987 to 2009.
  
  
  METHODS
  Denmark, birth registration data.
  
  
  METHODS
  Women with a first singleton delivery after 37 weeks were followed until the end of 2010, from a first birth to include subsequent live births. We used Cox's proportional hazards model stratified by parity to compare the likelihood for subsequent delivery according to mode of delivery at first and later births, estimating maternal age effects and lag time to next delivery.
  
  
  METHODS
  Likelihood of a subsequent live-born child by previous delivery mode.
  
  
  RESULTS
  We identified 642,052 women with a first delivery. Compared with women with a non-instrumental vaginal delivery, delivering a child by elective cesarean section implied a 23% (95% CI 0.76-0.787) decreased likelihood for subsequent delivery. Emergency cesarean section meant 16% fewer (95% CI 0.84-0.85), and vaginal instrumental delivery 4% fewer subsequent deliveries (95% CI 0.95-0.96). Hazard ratios were largely unchanged after controlling for parity and year of birth. Small age-trends were seen, with hazard ratios affected by maternal age at birth. Delivery mode at first birth affected marginally the time lag until next birth.
  
  
  CONCLUSIONS
  Fecundity, measured as likelihood of a successive live-born child, varied with mode of delivery at the first and also subsequent births. A first or later delivery by cesarean section implied decreased likelihood of subsequent delivery compared with women with a first vaginal birth.
authors.affiliation: Department of Obstetrics, Rigshospitalet University Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Caroline
authors.initials: C
authors.lastname: Fussing-Clausen
authors.forename: Reynir T
authors.initials: RT
authors.lastname: Geirsson
authors.forename: Thomas
authors.initials: T
authors.lastname: Hansen
authors.forename: Steen
authors.initials: S
authors.lastname: Rasmussen
authors.forename: Øjvind
authors.initials: Ø
authors.lastname: Lidegaard
authors.forename: Morten
authors.initials: M
authors.lastname: Hedegaard
mesh_terms: D000293:Adolescent; D000328:Adult; D001719:Birth Certificates; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000379:methods / Q000706:statistics & numerical data; D003718:Denmark / Q000453:epidemiology; D004630:Emergencies / Q000453:epidemiology; D005260:Female; D005298:Fertility; D006801:Humans; D008423:Maternal Age; D009321:Natural Childbirth / Q000706:statistics & numerical data*; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D018873:Pregnancy Rate; D016016:Proportional Hazards Models; D017584:Reproductive History
keywords: Fertility; elective cesarean section; emergency cesarean section; fecundity; instrumental vaginal delivery; mode of delivery; vaginal birth