title: The cumulative probability of liveborn multiples after in vitro fertilization: a cohort study of more than 10,000 women.
abstract: OBJECTIVE
  To estimate the cumulative probability of liveborn multiples after IVF to improve patient counseling regarding this significant morbidity.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Large academic-affiliated infertility practice.
  
  
  METHODS
  A total of 10,169 women were followed from their first fresh, nondonor IVF cycle through up to six fresh and frozen IVF cycles from 2000-2010.
  
  
  METHODS
  None.
  
  
  METHODS
  Delivery of a liveborn infant(s).
  
  
  RESULTS
  After three IVF cycles the cumulative live birth rate (CLBR) was 53.2%. The singleton, twin, and triplet CLBRs were 38.0%, 14.5%, and 0.7%. After six IVF cycles the CLBR was 73.8%, with 52.8%, 19.8%, 1.3% for singletons, twins, and triplets. Of the 5,433 live births, 71.4% were singletons, 27.1% were twins, and 1.5% were triplets. Women more than 39 years had the lowest incidence of liveborn multiples with CLBRs of 5.2% after three cycles and 9.5% after six cycles. The twin CLBR doubled from cycles 1 through 3 with the rate of increase slowing from cycles 3 through 6. Although very low in absolute terms, the triplet CLBR also doubled from cycles 1 through 3 and doubled again from cycles 3 through 6. Of the 1,970 pregnancies that began as multifetal on ultrasound, 77.4% resulted in liveborn multiples.
  
  
  CONCLUSIONS
  Providers should be aware of the cumulative probability of liveborn multiples to effectively counsel patients on this important issue. With nearly three-quarters of all women having live birth after up to six IVF cycles, it is encouraging to report a low incidence of liveborn multiples.
authors.affiliation: Department of Obstetrics and Gynecology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA. bethmalizia@gmail.com
authors.forename: Beth A
authors.initials: BA
authors.lastname: Malizia
authors.forename: Laura E
authors.initials: LE
authors.lastname: Dodge
authors.forename: Alan S
authors.initials: AS
authors.lastname: Penzias
authors.forename: Michele R
authors.initials: MR
authors.lastname: Hacker
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data*; D006801:Humans; D007246:Infertility / Q000453:epidemiology* / Q000628:therapy*; D050498:Live Birth / Q000453:epidemiology*; D008404:Massachusetts / Q000453:epidemiology; D009099:Multiple Birth Offspring / Q000706:statistics & numerical data*; D011247:Pregnancy; D018873:Pregnancy Rate; D015995:Prevalence; D012189:Retrospective Studies; D016896:Treatment Outcome