title: Lag time from ovulation trigger to oocyte aspiration and oocyte maturity in assisted reproductive technology cycles: a retrospective study.
abstract: OBJECTIVE
  To study the correlation between the lag time from ovulation trigger to oocyte aspiration and the proportion of metaphase II (MII) mature oocytes aspirated.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Fertility and IVF center in an academic regional hospital.
  
  
  METHODS
  A total of 511 women undergoing IVF-intracytoplasmic sperm injection at our center, with at least one oocyte available for maturity determination.
  
  
  METHODS
  Data were retrieved from patient electronic databases and files. Demographic data, hormone treatments and ovarian response, and the time of ovulation trigger and oocyte aspiration were recorded.
  
  
  METHODS
  The primary outcome was the proportion of MII mature oocytes relative to the total number of oocytes aspirated and allocated to intracytoplasmic sperm injection. Pregnancy rates and clinical pregnancy rates were secondary outcomes.
  
  
  RESULTS
  There were fewer MII mature oocytes when the lag time between oocyte trigger and aspiration was between 33.45 hours and 34.45 hours. The proportion of MII oocytes seems to increase up to a 35-hour lag time and then stabilizes up to 38 hours. Pregnancy and clinical pregnancy rates did not differ among the different time groups studied.
  
  
  CONCLUSIONS
  Oocyte aspiration should be scheduled at least 35 hours after ovulation trigger. Oocytes can be aspirated in a 3-hour window of time between 35 and 38 hours without compromising results. Further research should elucidate whether even longer lag times will improve the proportion of MII mature oocytes.
authors.affiliation: Fertility and In Vitro Fertilization Unit, Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel. Electronic address: amirwe5@gmail.com.
authors.forename: Amir
authors.initials: A
authors.lastname: Weiss
authors.affiliation: Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Neril
authors.affiliation: Fertility and In Vitro Fertilization Unit, Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.
authors.forename: Joel
authors.initials: J
authors.lastname: Geslevich
authors.affiliation: Fertility and In Vitro Fertilization Unit, Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel; Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Lavee
authors.affiliation: Fertility and In Vitro Fertilization Unit, Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.
authors.forename: Ronit
authors.initials: R
authors.lastname: Beck-Fruchter
authors.affiliation: Fertility and In Vitro Fertilization Unit, Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel.
authors.forename: Joanne
authors.initials: J
authors.lastname: Golan
authors.affiliation: Fertility and In Vitro Fertilization Unit, Department of Obstetrics and Gynecology, Emek Medical Center, Afula, Israel; Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Eliezer
authors.initials: E
authors.lastname: Shalev
mesh_terms: D000328:Adult; D004334:Drug Administration Schedule; D005260:Female; D005298:Fertility / Q000187:drug effects*; D005300:Fertility Agents, Female / Q000008:administration & dosage*; D005307:Fertilization in Vitro; D006801:Humans; D059471:In Vitro Oocyte Maturation Techniques; D007247:Infertility, Female / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008677:Metaphase / Q000187:drug effects; D054315:Oocyte Retrieval / Q000379:methods; D009865:Oocytes / Q000187:drug effects*; D010062:Ovulation Induction / Q000379:methods*; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D013396:Suction; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D005300:Fertility Agents, Female
keywords: Assisted reproductive technology; ICSI; MII oocytes; hCG