title: Effect of time between human chorionic gonadotropin injection and egg retrieval is age dependent.
abstract: OBJECTIVE
  To investigate whether egg retrieval at ≥36.5 hours improves IVF outcomes in women aged ≥40 years.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Academic medical center.
  
  
  METHODS
  First-attempt autologous IVF cycles without preimplantation genetic diagnosis, IUI conversion, or intentional delayed egg retrieval were included (n=3,231). Cycles were stratified by age and hCG exposure (<36.5 vs. ≥36.5 hours).
  
  
  METHODS
  None.
  
  
  METHODS
  Oocyte yield, maturity, fertilization, embryo quality, implantation, clinical pregnancy, and live birth were analyzed, controlling for age and gonadotropins. Stimulation type, hMG use, stimulation days, day-3 FSH level, and diagnosis were evaluated as potential confounders. Multivariable regression analyses were performed and Wald tests for trend calculated.
  
  
  RESULTS
  No consistent differences in oocyte yield, maturity, fertilization, or embryo quality were detected. No absolute differences in outcomes were noted among group comparisons. However, as age increased, significant trends toward improved implantation, clinical pregnancy, and live birth were detected at ≥36.5 hours.
  
  
  CONCLUSIONS
  Extending exposure to hCG for ≥36.5 hours may be beneficial in patients aged≥40 years. A prospective, randomized study is warranted to determine whether retrieval time merits revision for patients of advanced age, as well as the age cutoffs at which such protocols should be applied.
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Reichman
authors.forename: Stacey A
authors.initials: SA
authors.lastname: Missmer
authors.forename: Katharine F
authors.initials: KF
authors.lastname: Berry
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Ginsburg
authors.forename: Catherine
authors.initials: C
authors.lastname: Racowsky
mesh_terms: D000328:Adult; D000367:Age Factors; D006063:Chorionic Gonadotropin / Q000008:administration & dosage*; D015331:Cohort Studies; D004334:Drug Administration Schedule; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage; D006801:Humans; D007315:Insemination, Artificial / Q000379:methods; D008423:Maternal Age; D054315:Oocyte Retrieval / Q000379:methods*; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin; D005300:Fertility Agents, Female