title: Fixed versus flexible gonadotropin-releasing hormone antagonist administration in in vitro fertilization: a randomized controlled trial.
abstract: OBJECTIVE
  To evaluate whether the incidence of luteinizing hormone (LH) rise is reduced by using a flexible compared with a fixed day-6 protocol of GnRH antagonist administration.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  Tertiary university hospital.
  
  
  METHODS
  Patients undergoing in vitro fertilization (n = 146).
  
  
  METHODS
  Ovarian stimulation was performed using recombinant FSH and GnRH antagonists. GnRH antagonist cetrorelix (0.25 mg/d) was started either on day 6 of stimulation (fixed group) or when LH was >10 IU/L, and/or a follicle with mean diameter >12 mm was present, and/or serum E(2) was >150 pg/mL. Patient monitoring was initiated on day 3 of stimulation.
  
  
  METHODS
  Incidence of LH rise.
  
  
  RESULTS
  No statistically significant difference was observed between the flexible and fixed groups regarding the incidence of LH rise, which was lower in the flexible group (11.0% vs. 15.1%, difference -4.1%, 95% confidence interval -15.4% to +7.1%). No LH surges were observed in any of the patients studied.
  
  
  CONCLUSIONS
  Flexible antagonist administration from day 3 onward does not appear to reduce the incidence of LH rises compared with fixed antagonist administration on day 6 of stimulation.
authors.affiliation: Unit for Human Reproduction, First Department of Obstetrics and Gynecology, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Efstratios M
authors.initials: EM
authors.lastname: Kolibianakis
authors.forename: Christos A
authors.initials: CA
authors.lastname: Venetis
authors.forename: Lydia
authors.initials: L
authors.lastname: Kalogeropoulou
authors.forename: Evangelos
authors.initials: E
authors.lastname: Papanikolaou
authors.forename: Basil C
authors.initials: BC
authors.lastname: Tarlatzis
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage; 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; D007246:Infertility / Q000097:blood / Q000628:therapy*; D007986:Luteinizing Hormone / Q000097:blood; D010062:Ovulation Induction / Q000379:methods; D011247:Pregnancy; D018873:Pregnancy Rate
chemical_list: D005300:Fertility Agents, Female; D006727:Hormone Antagonists; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; C062876:cetrorelix