title: Perinatel outcomes of singleton pregnancies achieved by in vitro fertilization: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To determine whether the incidence of adverse obstetric outcomes is higher in singleton pregnancies achieved by in vitro fertilization (IVF) than in spontaneously conceived singletons matched for maternal age.
  
  
  METHODS
  We used comprehensive search strategies to search MEDLINE and EMBASE databases. We selected case-control and cohort studies that compared singleton pregnancies conceived by IVF or intracytoplasmic sperm injection (ICSI) with spontaneously conceived singletons (matched for maternal age [case-control studies] or controlled for maternal age [cohort studies]). Two reviewers independently assessed titles, abstracts, and study quality and extracted data. Statistical analysis was performed with Review Manager for Windows (Version 4.2, Oxford, UK). We performed meta-analysis of dichotomous data, using odds ratios (ORs) as measures of effect size, with a random effects model. We followed the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines for meta-analysis of observational studies.
  
  
  RESULTS
  Singleton pregnancies resulting from IVF have increased rates of poor obstetric outcome, compared with spontaneously conceived singletons matched for maternal age, with increases in perinatal mortality (OR 2.40; 95% confidence interval [CI] 1.59-3.63), preterm birth at < 33 weeks' gestation (OR 2.99; 95% CI 1.54-5.80), preterm birth at < 37 weeks' gestation (OR 1.93; 95% CI 1.36-2.74), very low birth weight (< 1500 g) (OR 3.78; 95% CI 4.29-5.75), small for gestational age (OR 1.59; 95% CI 1.20-2.11), and congenital malformations (OR 1.41; CI 1.06-1.88).
  
  
  CONCLUSIONS
  IVF singleton pregnancies have increased rates of poor obstetric outcome, compared with spontaneously conceived singletons matched for maternal age.
authors.affiliation: Department of Obstetrics and Gynecology, The Ottawa Hospital, Ottawa, Ontario, Canada.
authors.forename: Sarah D
authors.initials: SD
authors.lastname: McDonald
authors.forename: Kellie
authors.initials: K
authors.lastname: Murphy
authors.forename: Joseph
authors.initials: J
authors.lastname: Beyene
authors.forename: Arne
authors.initials: A
authors.lastname: Ohlsson
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro; D020073:Gravidity; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D020554:Sperm Injections, Intracytoplasmic