Clomiphene citrate or anastrozole for ovulation induction in women with polycystic ovary syndrome? A prospective controlled trial

Abstract

Objective: To compare the effects of anastrozole (1 mg) and clomiphene citrate (CC; 100 mg) used for ovulation induction in women with polycystic ovary syndrome.

Design: Prospective controlled trial.

Setting: University teaching hospital and private-practice setting.

Patient(s): The study comprised a total of 216 infertile women (469 cycles) with polycystic ovary syndrome.

Intervention(s): Patients received anastrozole (1 mg/d; 115 patients, 243 cycles) for 5 days, starting on day 3 of menses. A matched historical group of patients with polycystic ovary syndrome who were treated with CC (100 mg/d; 101 patients, 226 cycles) was used as a control group. Timed intercourse was advised 24-36 hours after hCG injection.

Main outcome measure(s): Number of follicles, serum E(2), serum P, endometrial thickness, and pregnancy and miscarriage rates.

Result(s): The mean age, parity, and duration of infertility in both groups were similar, but statistically significantly more polycystic ovaries were found in the anastrozole group (odds ratio = 2.44; 95% confidence interval = 1.19-5.02). The total numbers of follicles were significantly higher in the CC group (3.8 +/- 0.6 vs. 3.4 +/- 0.5). Endometrial thickness at the time of hCG administration was significantly greater in the anastrozole group (10.1 +/- 0.22 mm vs. 8.2 +/- 0.69 mm). The duration of stimulation was similar in the two groups. Ovulation occurred in 165 (67.9%) of 243 cycles in the anastrozole group and in 150 (68.6%) of 226 cycles in the CC group without significant difference. Serum P was significantly higher in the CC group (7.1 +/- 1.11 vs. 8.1 +/- 0.88 ng/mL). The pregnancy and miscarriage rates were similar in the two groups.

Conclusion(s): Anastrozole was associated with significantly fewer mature and growing follicles, thicker endometrium, and slightly higher pregnancy rate. Anastrozole may be helpful in situations in which multiple pregnancy is not desirable or the risk of ovarian hyperstimulation syndrome is high.