title: Worldwide prevalence of adverse pregnancy outcomes among singleton pregnancies after in vitro fertilization/intracytoplasmic sperm injection: a systematic review and meta-analysis.
abstract: OBJECTIVE
  The worldwide prevalence of adverse pregnancy outcomes (APOs) in singleton pregnancies after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) is suggested to vary; however, a complete overview is missing. The aim of this review is to estimate the worldwide prevalence of APOs associated with IVF/ICSI singleton pregnancies.
  
  
  METHODS
  PubMed, Google Scholar, Cochrane Libraries, and Chinese databases were searched for studies assessing APOs among IVF/ICSI singleton births through March 2016. The prevalence estimates were summarized and analyzed by meta-analysis.
  
  
  RESULTS
  Fifty-two cohort studies, with 181,741 IVF/ICSI singleton births and 4,636,508 spontaneously conceived singleton births, were selected for analysis. Among IVF/ICSI singleton pregnancies, pooled estimates were 10.9% [95% confidence interval (CI) 10.0-11.8] for preterm birth, 2.4% (95% CI 1.9-3.0) for very preterm birth, 8.7% (95% CI 7.4-10.2) for low birth weight, 2.0% (95% CI 1.5-2.6) for very low birth weight, 7.1% (95% CI 5.5-9.2) for small for gestational age, 1.1% (95% CI 0.9-1.3) for perinatal mortality, and 5.7% (95% CI 4.7-6.9) for congenital malformations. The IVF/ICSI singleton pregnancies have higher prevalence of APOs compared with those conceived naturally (all P = 0.000). Significant differences in different continents, countries, income groups, and type of assisted conception were found.
  
  
  CONCLUSIONS
  The IVF/ICSI singleton pregnancies are at a higher prevalence of adverse perinatal outcomes compared with those conceived naturally. Important geographical differences were found. Yet, population-wide prospective APO registries covering the entire world population for IVF/ICSI pregnancies are needed to determine the exact perinatal prevalence.
authors.affiliation: Information Management Division, Hunan Provincial Maternal and Child Health Care Hospital, 53 Xiangchun Road, Changsha, 410008, Hunan, China. qinjiabi123@163.com.|Division of Medical Genetics, Hunan Provincial Maternal and Child Health Care Hospital, 53 Xiangchun Road, Changsha, 410008, Hunan, China. qinjiabi123@163.com.
authors.forename: Jia-Bi
authors.initials: JB
authors.lastname: Qin
authors.affiliation: Division of Medical Genetics, Hunan Provincial Maternal and Child Health Care Hospital, 53 Xiangchun Road, Changsha, 410008, Hunan, China.
authors.forename: Xiao-Qi
authors.initials: XQ
authors.lastname: Sheng
authors.affiliation: Enrollment and Employment Office, Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China.
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.affiliation: Reproductive Medicine Center, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China.
authors.forename: Shi-You
authors.initials: SY
authors.lastname: Gao
authors.affiliation: Maternity Department, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan, China.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: You
authors.affiliation: Department of Epidemiology and Health Statistics, School of Public Health, Central South University, Changsha, Hunan, China.
authors.forename: Tu-Bao
authors.initials: TB
authors.lastname: Yang
authors.affiliation: Division of Medical Genetics, Hunan Provincial Maternal and Child Health Care Hospital, 53 Xiangchun Road, Changsha, 410008, Hunan, China. wangh1234@hotmail.com.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects*; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011248:Pregnancy Complications / Q000209:etiology*; D011256:Pregnancy Outcome; D015995:Prevalence; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic / Q000009:adverse effects*
keywords: Adverse pregnancy outcomes; In vitro fertilization; Intracytoplasmic sperm injection; Meta-analysis; Prevalence estimates