title: Cumulative live-birth rates per total number of embryos needed to reach newborn in consecutive in vitro fertilization (IVF) cycles: a new approach to measuring the likelihood of IVF success.
abstract: OBJECTIVE
  To report the use of cumulative live-birth rates (CLBRs) per ovarian stimulation cycle to measure the success of IVF is proving to be the most accurate method for advising couples who failed to conceive, although the accuracy yielded is relatively low, and cycle outcome is highly dependent on the number of embryos replaced. Our aim with this work is to report the CLBRs of IVF as a function of the number of embryos required to reach a live birth (EmbR), considering age, day of ET, and infertility etiology.
  
  
  METHODS
  Survival curves and Kaplan-Meier methods to analyze CLBR in a retrospective cohort with respect to the number of EmbR.
  
  
  METHODS
  University-affiliated infertility center.
  
  
  METHODS
  Infertile couples undergoing IVF using own oocytes.
  
  
  METHODS
  None.
  
  
  METHODS
  CLBR per embryo transferred.
  
  
  RESULTS
  CLBRs increase rapidly between 1 and 5 EmbR, moderately between 5 and 15, and slowly thereafter. Live-birth rates rise more slowly when embryos are transferred on days 2-3 rather than on days 5-6, with comparable long-term results. Women's age is a negative factor from 35 to 37 years old, with a dramatic decrease in live-birth rates beyond age 40 years. In addition, there are significant worse results in endometriosis patients.
  
  
  CONCLUSIONS
  The relationship between CLBR and number of EmbR provides realistic and precise information regarding IVF success and can be used to guide couples and practitioners.
authors.affiliation: Instituto Universitario IVI Valencia, University of Valencia, Valencia, Spain. nicolas.garrido@ivi.es
authors.forename: Nicolás
authors.initials: N
authors.lastname: Garrido
authors.forename: José
authors.initials: J
authors.lastname: Bellver
authors.forename: José
authors.initials: J
authors.lastname: Remohí
authors.forename: Carlos
authors.initials: C
authors.lastname: Simón
authors.forename: Antonio
authors.initials: A
authors.lastname: Pellicer
mesh_terms: D000328:Adult; D001723:Birth Rate / Q000639:trends*; D015331:Cohort Studies; D004624:Embryo Transfer / Q000592:standards / Q000639:trends*; D005260:Female; D005307:Fertilization in Vitro / Q000592:standards / Q000639:trends*; D006801:Humans; D007231:Infant, Newborn; D053208:Kaplan-Meier Estimate; D050498:Live Birth; D008297:Male; D011247:Pregnancy; D012189:Retrospective Studies