title: The time interval between hCG priming and oocyte retrieval in ART program: a meta-analysis.
abstract: OBJECTIVE
  To evaluate the relationship between different hCG priming-to-oocyte retrieval intervals and assisted reproductive technology (ART) outcome.
  
  
  METHODS
  We systematically searched PubMed, EMBASE, the Cochrane Library, Science Citation Index, Chinese biomedicine (CBM) literature database, and Chinese Journal Full-text Database for randomized controlled trials (RCTs) published up to November 2010. Data was extracted from the studies by two independent reviewers. Statistical analysis was performed with Cochrane Collaboration's Review Manager (RevMan) 5.0.2. From extracted data, Risk Ratio (RR) with 95% confidence interval (CI) was calculated.
  
  
  RESULTS
  5 RCTs totaling 895 participants were included. Oocyte maturation rate was higher in the long interval group compared with short interval group (RR, 0.67; 95% CI, 0.62-0.73). There were no significant difference between the two groups with regard to fertilization rate (RR, 0.99; 95% CI, 0.94-1.04), implantation rate (RR, 0.91; 95% CI, 0.40-2.04), and pregnancy rate (RR, 0.79; 95% CI, 0.58-1.08).
  
  
  CONCLUSIONS
  The percentage of mature (MII) oocytes can be increased by prolonging the interval between hCG priming and oocyte retrieval. The prolonged interval could not increase the fertilization rate, implantation rate, and pregnancy rate. Although there was evidence to confirm the results, they still need to be confirmed by large-sample, multicenter, randomized controlled trials. The time interval dependent mechanisms responsible for ART performance need to be elucidated.
authors.affiliation: The Reproductive Medicine Center, the First Hospital of Lanzhou University, Lanzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Xue-Hong
authors.initials: XH
authors.lastname: Zhang
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Wang
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Liu
authors.forename: Li-Hui
authors.initials: LH
authors.lastname: Zhao
authors.forename: Shi-Long
authors.initials: SL
authors.lastname: Xue
authors.forename: Ke-Hu
authors.initials: KH
authors.lastname: Yang
mesh_terms: D006063:Chorionic Gonadotropin / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D054315:Oocyte Retrieval; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D016032:Randomized Controlled Trials as Topic; D027724:Reproductive Techniques, Assisted; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin