Follicular and endocrine response to anastrozole versus clomiphene citrate administered in follicular phase to normoovulatory women: a randomized comparison

Abstract

To compare the effect on follicular growth and endocrine parameters of follicular phase administration of anastrozole to healthy, normoovulatory women in doses of 1 or 5 mg, respectively, with the conventional dosing regimen for ovulation induction with clomiphene citrate (CC). Randomized, assessor-blinded, single-center, three-armed study. University-affiliated, tertiary referral center. Thirty-two, normoovulatory, normogonadotropic women. Administration of anastrozole 1 mg (group A1), anastrozole 5 mg (group A5), or CC 50 mg (group CC50) from cycle days 3 to 7. Number of follicles >or=15 mm and >or=10 mm on the day of the endogenous LH surge. The mean number of follicles >or=15 mm on the day of LH surge was 1.4 +/- 0.5, 1.0 +/- 0.4, and 0.8 +/- 0.4 in groups CC50, A1, and A5, respectively, which was statistically significant. Furthermore, a statistically significant difference between groups was found for the size of the growing follicular cohort (follicles >or=10 mm) on cycle days 8 and 10 and on the day of LH surge. The area under the curve (adjusted for baseline values on cycle day 3 and time frame of assessment) of follicular phase E(2) levels was significantly different among the groups that were compared (223.0 +/- 97.5, 69.2 +/- 40.0, and 83.4 +/- 36.4 for groups CC50, A1, and A5, respectively). CC 50 mg exerts a stronger stimulatory effect on follicular growth compared with anastrozole in doses of 1 or 5 mg. Anastrozole administration results in lower follicular phase E(2) levels.