title: Gonadotropin-releasing hormone agonist use in assisted reproduction cycles: the influence of long and short regimens on pregnancy rates.
abstract: OBJECTIVE
  To compare the efficacy of GnRH agonists used in either the flare (short) or down-regulation (long) regimen as part of IVF or GIFT treatment cycles.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Three IVF clinics.
  
  
  METHODS
  One thousand two hundred forty-four couples accepted for IVF or GIFT treatment at participating clinics.
  
  
  METHODS
  In vitro fertilization or GIFT protocols standard to each clinic were recorded.
  
  
  METHODS
  Treatment cycle characteristics and outcomes, including E2 level, number of oocytes retrieved, and clinical pregnancy rate.
  
  
  RESULTS
  At site 1, there were 146 clinical pregnancies in 980 flare cycles, for a pregnancy rate of 14.9%, compared with 148 clinical pregnancies in 650 down-regulation cycles, for a pregnancy rate of 22.8%. This difference persisted after adjustment for age, primary infertility diagnosis, GIFT or IVF therapy, and year of treatment, and appeared to be mediated largely by the number of oocytes retrieved (mean, 9.8 for downregulation and 8.7 for flare in the first cycle). Despite having fewer oocytes retrieved, women who received flare regimens had higher E2 levels before hCG administration.
  
  
  CONCLUSIONS
  Women who received GnRH agonists in a flare regimen had 11% fewer oocytes retrieved and a 35% reduction in the clinical pregnancy rate compared with those who received them in a down-regulation regimen; this difference was not explained by patient selection factors.
authors.affiliation: Obstetrics and Gynecology Epidemiology Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Cramer
authors.forename: D R
authors.initials: DR
authors.lastname: Powers
authors.forename: S P
authors.initials: SP
authors.lastname: Oskowitz
authors.forename: R F
authors.initials: RF
authors.lastname: Liberman
authors.forename: M D
authors.initials: MD
authors.lastname: Hornstein
authors.forename: P M
authors.initials: PM
authors.lastname: McShane
authors.forename: R L
authors.initials: RL
authors.lastname: Barbieri
mesh_terms: D000328:Adult; D000367:Age Factors; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists*; D006801:Humans; D007246:Infertility / Q000628:therapy*; D016015:Logistic Models; D008297:Male; D008597:Menstrual Cycle / Q000187:drug effects; D009866:Oogenesis / Q000187:drug effects; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D006063:Chorionic Gonadotropin; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D005640:Follicle Stimulating Hormone