title: Luteal phase estradiol versus luteal phase GnRH antagonist administration: their effects on antral follicular size coordination and basal hormonal levels.
abstract: BACKGROUND
  The differential efficacy between long GnRH agonist with antagonist can partly be due to the preexisting differences in the early antral follicles before ovarian stimulation.
  
  
  OBJECTIVE
  To compare the effect of pretreatment by estradiol with GnRH antagonist on antral follicular size coordination and basal hormone levels in GNRH antagonist protocol.
  
  
  METHODS
  On cycle day 3 (control/day 3), women underwent measurements of early antral follicles by ultrasound and serum FSH and ovarian hormones then were randomized to receive oral estradiol 4mg/day (n=15) or 3mg cetrorelix acetate (n=15) in luteal phase before subsequent antagonist protocol. Participants were re-evaluated as on control/day 3.
  
  
  RESULTS
  There was a significant reduction of mean follicular sizes in each group after medical intervention (7.63±2.11 Vs. 4.30±0.92 in group A and 8.73±1.96 Vs. 4.13±1.11 in group B) (p=0.0001). The magnitude of follicular size reduction was significantly higher in group B (-4.60±2.04 Vs. -3.33±2.28) (0.027). There was a non significant attenuation of follicular size discrepancies in two groups. FSH and inhibin B levels in the day 3 of the next cycle in both groups were significantly decreased but did not have significant difference between two groups.
  
  
  CONCLUSIONS
  Both luteal E2 and premenstrual GnRH antagonist administration reduces the follicular sizes significantly and GnRH antagonist acts more potently than E2 in this way but attenuation of follicular size discrepancies in both treatment is not significant.
authors.affiliation: Valie-Asr Reproductive Health Research Center, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Batool
authors.initials: B
authors.lastname: Rashidi
authors.affiliation: Department of Obstetrics and Gynecology, Aria Hospital, Faculty of Medicine, Islamic Azad University of Medical Sciences, Mashhad Branch, Mashhad, Iran.
authors.forename: Roya
authors.initials: R
authors.lastname: Nasiri
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.
authors.forename: Haleh
authors.initials: H
authors.lastname: Rahmanpour
authors.affiliation: Valie-Asr Reproductive Health Research Center, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Ensieh
authors.initials: E
authors.lastname: Shahrokh Tehraninejad
authors.affiliation: Valie-Asr Reproductive Health Research Center, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Deldar
keywords: Estradiol; Follicular synchronization; GnRH antagonist