title: Does the estradiol level on the day of human chorionic gonadotrophin administration have an impact on pregnancy rates in patients treated with rec-FSH/GnRH antagonist?
abstract: BACKGROUND
  The purpose of this prospective observational study was to evaluate the association between estradiol (E(2)) levels on the day of human chorionic gonadotrophin (hCG) administration and pregnancy rates in a recombinant FSH (rec-FSH) antagonist fixed protocol.
  
  
  METHODS
  A group of 207 patients (<or=39 years of age), treated by IVF/ICSI, received 200 IU/day rec-FSH from Day 2 of the cycle and daily GnRH antagonist starting on Day 6 of stimulation. The criteria for hCG administration included only the presence of >or=3 follicles of >or=17 mm diameter. One to two embryos were transferred on Day 3 after oocyte retrieval.
  
  
  RESULTS
  The area under the curve (AUC) for E(2) on the day of hCG could not distinguish between pregnant and non-pregnant women (AUC:0.5; 95% confidence interval (CI): 0.42-0.59). No significant difference was observed between the three percentile groups of E(2) values on the day of hCG administration [group 1, lower 25th percentile (<1142 pg/ml); group 2, medium 50th percentile (1142-2446 pg/ml) and group 3, higher 75th percentile (>2446 pg/ml)] for the ongoing pregnancy rates (P = 0.52). On the contrary, the linear regression model showed that higher E(2) values on the day of hCG administration significantly improved the scores of transferred embryos (P = 0.01) as well as the total embryo score (P = 0.02). Yet subgroup analysis only in this high responders group revealed lower E(2) and progesterone levels on the day of hCG in pregnant women compared with the non-pregnant (P = 0.01).
  
  
  CONCLUSIONS
  E(2) concentrations on the day of hCG administration in GnRH antagonist cycles are not associated with pregnancy rates. A potential deleterious impact of estradiol on endometrial receptivity is shown for the high responders who have high E(2) levels and improved embryo quality without a concomitant rise in pregnancy rate.
authors: Centre for Reproductive Medicine, Dutch-Speaking Free University Brussels, Laarbeeklaan 101, 1090 Brussels, Belgium. mimikyrou@yahoo.gr
authors: D
authors: D
authors: Kyrou
authors: B
authors: B
authors: Popovic-Todorovic
authors: H M
authors: HM
authors: Fatemi
authors: C
authors: C
authors: Bourgain
authors: P
authors: P
authors: Haentjens
authors: L
authors: L
authors: Van Landuyt
authors: P
authors: P
authors: Devroey
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood*; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D007987:Gonadotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D006801:Humans; D016014:Linear Models; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D011994:Recombinant Proteins / Q000494:pharmacology*
chemical_list: D006063:Chorionic Gonadotropin; D011994:Recombinant Proteins; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D005640:Follicle Stimulating Hormone