title: Follicular growth and development under continuous gonadotropin-releasing hormone antagonist administration.
abstract: OBJECTIVE
  Ovarian follicle and cyst formation have been recognized as an advance phenomenon associated with GnRH agonist administration. With the use of GnRH antagonists, pituitary suppression is immediate and no flare effect and follicle growth are expected. We describe two patients who developed a dominant follicle and presumably ovulated in response to hCG triggering under continuous sole administration of a GnRH antagonist.
  
  
  METHODS
  Case report.
  
  
  METHODS
  An IVF unit at a university hospital.
  
  
  METHODS
  Two young healthy female patients undergoing IVF because of male-factor infertility.
  
  
  METHODS
  Continuous daily administration of a GnRH antagonist from menstruation with the aim of achieving ovarian suppression.
  
  
  METHODS
  Endocrine and ultrasound characteristics of follicular growth.
  
  
  RESULTS
  Both patients developed a dominant follicle under sole administration of a GnRH antagonist, accompanied by a gradual rise in serum estradiol and endometrial thickness which culminated in a spontaneous LH surge. Ovulation was triggered by hCG and mid-luteal progesterone levels were suggestive of ovulation.
  
  
  CONCLUSIONS
  We describe for the first time the development of a dominant follicle and presumable ovulation under continuous administration of a GnRH antagonist. Serum gonadotropin concentrations indicate that the pituitary failed to suppress in both patients. The exact mechanism of this phenomenon remains to be elucidated.
authors.affiliation: Department of Obstetrics and Gynecology, Edith Wolfson Medical Center, Tel Aviv University, Tel Aviv, Israel. a_w@zahav.net.il
authors.forename: Ariel
authors.initials: A
authors.lastname: Weissman
authors.forename: Amir
authors.initials: A
authors.lastname: Ravhon
authors.forename: Galia
authors.initials: G
authors.lastname: Biran
authors.forename: Dan
authors.initials: D
authors.lastname: Levin
authors.forename: Abraham
authors.initials: A
authors.lastname: Golan
authors.forename: David
authors.initials: D
authors.lastname: Levran
mesh_terms: D000328:Adult; D004334:Drug Administration Schedule; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors*; D006801:Humans; D007231:Infant, Newborn; D007248:Infertility, Male / Q000628:therapy; D008297:Male; D006080:Ovarian Follicle / Q000187:drug effects* / Q000254:growth & development*; D010062:Ovulation Induction / Q000379:methods; D011247:Pregnancy; D011256:Pregnancy Outcome
chemical_list: D007987:Gonadotropin-Releasing Hormone; C062876:cetrorelix