Pregnancies following use of metformin for ovulation induction in patients with polycystic ovary syndrome.

Objective: To assess pregnancy outcome in anovulatory infertility patients diagnosed with polycystic ovary syndrome (PCOS) who were treated with metformin.

Design: Case series.

Setting: Outpatient.

Patient(s): Anovulatory patients (n = 48) with a diagnosis of PCOS based on clinical, diagnostic, and laboratory evaluations were enrolled in the study over a 15-month period.

Intervention(s): Metformin was started at 500 mg b.i.d. for 6 weeks and then increased to 500 mg t.i.d. if no ovulation occurred. Clomiphene citrate (CC; 50 mg) was added if no ovulatory response occurred after 6 weeks.

Main Outcome Measure(s): Resumption of menses, presumptive ovulation, and pregnancy.

Result(s): Nineteen of 48 (40%) patients resumed spontaneous menses following treatment and showed presumptive evidence of ovulation with metformin alone; 15/48 (31%) required CC (50 mg) in conjunction with metformin therapy, and 10 of these 15 (67%) had evidence of ovulation; 20/48 (42%) conceived with a median time to conception of 3 months, and 7 of these 20 (35%) had spontaneous abortions (SAB); 19/48 (40%) had gastrointestinal-related side effects, and 5 of 48 patients (10%) had to decrease the dosage of metformin. Only 1 patient discontinued therapy.

Conclusion(s): Metformin alone in patients with PCOS results in a substantial number of pregnancies, with 69% (20/29) of those who ovulated conceiving in less than 6 months.