title: The use of gonadotropin-releasing hormone antagonist in a flexible protocol: a pilot study.
abstract: OBJECTIVE
  The purpose of this study was to investigate the efficacy of a flexible protocol of starting gonadotropin-releasing hormone antagonist according to the size of the leading follicle.
  
  
  METHODS
  This was a pilot study that included 123 couples who were undergoing in vitro fertilization/intracytoplasmic sperm injection cycles at the Egyptian IVF-ET Center. Couples were recruited into two groups: group I (n=64), gonadotropin-releasing hormone antagonist was administered when the diameter of the leading follicle reached 16 mm; group II (n=59), gonadotropin-releasing hormone antagonist was administered on day 6 of stimulation.
  
  
  RESULTS
  The mean number of antagonist injections was significantly lower in the flexible protocol compared to the fixed protocol (3.4+/-1.1 vs 5.3+/-1.8, P<.05). There was no significant difference between the two protocols regarding the number of embryos, implantation rate, clinical pregnancy rate (odds ratio, 0.85; 95% CI, 0.45-1.59) or multiple pregnancy rate (odds ratio, 1.26; 95% CI, 0.45-3.51).
  
  
  CONCLUSIONS
  Starting the gonadotropin-releasing hormone antagonist according to the size of the leading follicle is as effective as starting on a fixed day and reduces the antagonist administration.
authors.affiliation: Egyptian IVF-ET Center, and the Department of Obstetrics and Gynecology, Cairo University, Cairo, Egypt. ivf@link.net
authors.forename: Ragaa T
authors.initials: RT
authors.lastname: Mansour
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Aboulghar
authors.forename: Gamal I
authors.initials: GI
authors.lastname: Serour
authors.forename: Hesham G
authors.initials: HG
authors.lastname: Al-Inany
authors.forename: Yehia M
authors.initials: YM
authors.lastname: Amin
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Abou-Setta
mesh_terms: D000328:Adult; D004334:Drug Administration Schedule; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors*; D006727:Hormone Antagonists / Q000008:administration & dosage*; D006801:Humans; D007248:Infertility, Male / Q000188:drug therapy / Q000628:therapy*; D008297:Male; D006080:Ovarian Follicle / Q000503:physiopathology; D010865:Pilot Projects; D011247:Pregnancy; D018873:Pregnancy Rate; D020554:Sperm Injections, Intracytoplasmic
chemical_list: D006727:Hormone Antagonists; D007987:Gonadotropin-Releasing Hormone; C062876:cetrorelix