A randomized comparison of ovulation induction and hormone profile between the aromatase inhibitor anastrozole and clomiphene citrate in women with infertility

Abstract

Anastrozole has a high pregnancy rate, although it induces fewer ovulatory follicles compared with clomiphene citrate. The two drugs gave different responses of FSH, LH and E2 during stimulation cycles.

Anastrozole single-dose protocol in women with oligo- or anovulatory infertility: results of a randomized phase II dose–response study

“…Among patients who ovulated, midluteal endometrial thickness was slightly greater in patients receiving a single dose of anastrozole 5 mg than in patients receiving CC 50 mg/d for 5 days, which is in line with findings of the phase I study (19). This could explain the higher pregnancy rate with anastrozole 5 mg than with CC 50 mg/d among patients who ovulated (Supplemental Discussion).…”

“…A notable advantage of anastrozole treatment was the finding that patients generally had monofollicular growth, whereas approximately half of the patients developed multiple follicles in the CC cycles (19). As noted by Erickson et al (20), excessive androgen levels can inhibit follicular development and even ovulation; one explanation could be that increased androgen levels noted early in the cycle have an effect on follicular recruitment, resulting in more monofollicular development.…”

Anastrozole vs. clomiphene citrate in infertile women with ovulatory dysfunction: a phase II, randomized, dose-finding study

“…As confirmed by others (12)(13)(14), treatment with anastrozole is associated with significantly (P<.05) greater monofollicular development than that observed with CC. As noted in the singledose study (11), excessive androgen levels can inhibit follicular development and even ovulation (15).…”

Fertility Drugs and Young-Onset Breast Cancer: Results From the Two Sister Study

“…Treatment with ovulation-stimulating fertility drugs causes recruitment and maturation of multiple ovarian follicles, temporarily elevating estrogen; in women treated with clomiphene citrate (CC), the peak serum levels of estrogen are two-to threefold higher than normal (average: 200 pg/mL at peak) (3,4), and peak levels are even higher in women who undergo in vitro fertilization (IVF) treatment, which typically involves the use of folliclestimulating hormone (FSH)-containing drugs (5,6). If pregnancy results, the supernumerary ovarian corpora lutea produce both estrogen and progesterone and raise the levels far above normal in the first 9 weeks (7,8).…”