title: Confounding variables affecting in vitro fertilization success: a decade of experience.
abstract: OBJECTIVE
  To evaluate etiology of infertility, female age, ovarian response and stimulation protocol in affecting in vitro fertilization (IVF) success.
  
  
  METHODS
  Retrospective analysis was used. Computer records of all 5209 cycles initiated in 2391 couples from February 1, 1984 to December 31, 1993 were analyzed.
  
  
  RESULTS
  There were 644 intrauterine, 24 solely ectopic and 7 heterotopic pregnancies. Pregnancy rates increased with number of embryos transferred with a significant increase still found between transfer of three or four embryos. Multiple gestations also increased in association with an increasing number of embryos transferred. Pregnancy rates per cycle did not decline with repeated cycles. Reduced pregnancy rates were associated with a primary diagnosis of male infertility. Covariates associated with a better pregnancy rate were younger age of the female partner or higher peak preovulatory serum estradiol. Routine administration of GnRH-agonist was associated with a reduced cycle cancellation rate, an increase in oocytes retrieved and an improved pregnancy rate.
  
  
  CONCLUSIONS
  Couples with male infertility and increased female age should be counselled regarding the reduced prognosis for success.
authors.affiliation: Department of Gynaecology and Reproductive Medicine, University Hospital, London, Ontario, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Alsalili
authors.forename: A A
authors.initials: AA
authors.lastname: Yuzpe
authors.forename: I S
authors.initials: IS
authors.lastname: Tummon
authors.forename: J
authors.initials: J
authors.lastname: Parker
authors.forename: J S
authors.initials: JS
authors.lastname: Martin
authors.forename: J A
authors.initials: JA
authors.lastname: Nisker
authors.forename: S A
authors.initials: SA
authors.lastname: Daniel
mesh_terms: D000367:Age Factors; D016208:Databases, Factual; D004624:Embryo Transfer / Q000706:statistics & numerical data*; D004958:Estradiol / Q000097:blood; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data*; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists; D006801:Humans; D007248:Infertility, Male; D008297:Male; D011247:Pregnancy / Q000706:statistics & numerical data*; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol