title: Increased risk of preterm birth in singleton pregnancies resulting from in vitro fertilization-embryo transfer or gamete intrafallopian transfer: a meta-analysis.
abstract: OBJECTIVE
  To perform a systematic review of the literature to determine whether singleton pregnancies resulting from IVF-ET/GIFT are at higher risk for preterm birth (<37 weeks).
  
  
  METHODS
  Literature search and systematic review.
  
  
  METHODS
  Medical school.
  
  
  METHODS
  A MEDLINE search (1965-2000) was performed using the terms "premature labor," "infertility," "pregnancy complications," "gonadotropins," "pregnancy outcome," "preterm delivery," and "in vitro fertilization." Criteria for inclusion were English language, original research article, study patients conceived using IVF-ET (with or without intracytoplasmic sperm injection) or GIFT, pregnancy outcome reported compared with a control group (e.g., naturally conceived singletons at their hospital or a national reference), and prematurity clearly defined. Incomplete articles (e.g., abstracts), reports of other studies, and studies that failed to separate multiple from singleton gestations were excluded.
  
  
  METHODS
  Summary of relative risks of preterm birth.
  
  
  RESULTS
  Twenty-seven articles met all inclusion/exclusion criteria and were analyzed by meta-analysis. The random-effects summary relative risk of preterm birth in singleton pregnancies resulting from IVF-ET/GIFT was 1.98 (95% confidence interval, 1.77-2.22).
  
  
  CONCLUSIONS
  The risk of preterm birth in singleton pregnancies resulting from IVF-ET/GIFT is twice that of natural conceived pregnancies.
authors.affiliation: Department of Obstetrics, Gynecology and Women's Health, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, New Jersey 07101-1709, USA. mcgovepg@umdnj.edu
authors.forename: Peter G
authors.initials: PG
authors.lastname: McGovern
authors.forename: Amaury J
authors.initials: AJ
authors.lastname: Llorens
authors.forename: Joan H
authors.initials: JH
authors.lastname: Skurnick
authors.forename: Gerson
authors.initials: G
authors.lastname: Weiss
authors.forename: Laura T
authors.initials: LT
authors.lastname: Goldsmith
mesh_terms: D016001:Confidence Intervals; D004624:Embryo Transfer / Q000009:adverse effects*; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects*; D015181:Gamete Intrafallopian Transfer / Q000009:adverse effects*; D006801:Humans; D011247:Pregnancy; D047928:Premature Birth / Q000209:etiology*; D012306:Risk