title: A systematic review and meta-analysis of metformin among patients with polycystic ovary syndrome undergoing assisted reproductive technology procedures.
abstract: BACKGROUND
  Metformin is used among patients with polycystic ovary syndrome (PCOS), but findings for its effects on outcomes of assisted reproductive technology (ART) have been conflicting.
  
  
  OBJECTIVE
  To compare ART outcomes among women with PCOS who were and were not given metformin.
  
  
  METHODS
  Databases were searched for reports published in English between 2002 and 2013, using combinations of the terms "polycystic ovary syndrome," "PCOS," "insulin-sensitizing," and "metformin."
  
  
  METHODS
  Randomized controlled trials of metformin versus placebo among women with PCOS undergoing ART were included if they assessed rates of pregnancy, live birth, spontaneous abortion, multiple pregnancy, and/or ovarian hyperstimulation syndrome (OHSS).
  
  
  METHODS
  Data were extracted from included studies. The Mantel-Haenzel random-effects model was used for meta-analyses.
  
  
  RESULTS
  Twelve studies (1516 participants) were included. No significant differences were recorded between metformin and placebo groups for rates of pregnancy (risk ratio [RR] 1.11, 95% CI 0.92-1.33), live birth (RR 1.12, 0.92-1.36), spontaneous abortion (RR 1.00, 0.60-1.67), or multiple pregnancy (RR 0.96, 0.47-1.96). However, OHSS rate was significantly lower among patients who received metformin than among those who received placebo (RR 0.44, 0.26-0.77).
  
  
  CONCLUSIONS
  Metformin does not improve ART outcomes among patients with PCOS, but does significantly reduce their risk of OHSS.
authors: Reproductive Medicine Center, Department of Obstetrics and Gynecology, Clinical Medical School of Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou, China.
authors: Xiaman
authors: X
authors: Huang
authors: Reproductive Medicine Center, Department of Obstetrics and Gynecology, Clinical Medical School of Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou, China.
authors: Pin
authors: P
authors: Wang
authors: Division of Reproductive Endocrinology and Infertility, Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, USA.
authors: Reshef
authors: R
authors: Tal
authors: Reproductive Medicine Center, Department of Obstetrics and Gynecology, Clinical Medical School of Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou, China.
authors: Fang
authors: F
authors: Lv
authors: Maternity and Child Care Center, Yangzhou, China.
authors: Yuanyuan
authors: Y
authors: Li
authors: Reproductive Medicine Center, Department of Obstetrics and Gynecology, Clinical Medical School of Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou, China. Electronic address: zhangxiaomeiyz@163.com.
authors: Xiaomei
authors: X
authors: Zhang
mesh_terms: D000022:Abortion, Spontaneous; D000328:Adult; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D050498:Live Birth; D008687:Metformin / Q000627:therapeutic use*; D016471:Ovarian Hyperstimulation Syndrome / Q000209:etiology; D011085:Polycystic Ovary Syndrome / Q000150:complications / Q000188:drug therapy*; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple; D016032:Randomized Controlled Trials as Topic; D027724:Reproductive Techniques, Assisted / Q000706:statistics & numerical data*; D012307:Risk Factors
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin
keywords: Assisted reproductive technology; Metformin; Polycystic ovary syndrome; Pregnancy; Systematic review