Metformin as Effective as Clomiphene in PCOS.

Ovulation, pregnancy rates similar.

DENVER -- Two new studies add to previous data supporting the use of metformin as a fertility drug in women with polycystic ovary syndrome.

The insulin-sensitizing agent dramatically cut the elevated rate of early pregnancy loss in patients with polycystic ovary syndrome (PCOS) and also proved as effective as clomiphene citrate for induction of ovulation and achievement of pregnancy in two studies presented at the annual meeting of the Endocrine Society.

Dr. Helene Lavoie reported on 51 nondiabetic women with PCOS as defined by the presence of oligomenorrhea and biochemical hyperandrogenemia. The 28 with hyperinsulinemia while fasting or during a 75-g oral glucose tolerance test were placed on metformin at 500 mg t.i.d. Eleven of these women took metformin alone, while 17 others took the insulin sensitizer along with clomiphene citrate. The control group was composed of 23 PCOS patients who took clomiphene alone.

During a mean 7 months of follow-up, ovulation rates in the metformin-treated patients and those on clomiphene only were similar: 82% in those on metformin with or without clomiphene, and 78% with clomiphene.

Pregnancy as confirmed by ultrasound and a positive urinary HCG occurred in 63% of metformin-treated patients and 36% on clomiphene alone, a difference that wasn't statistically significant after adjusting for differences in patient age, said Dr. Lavoie of the University of Montreal.

Based upon this experience, she and her Montreal colleagues are now routinely using metformin to induce ovulation and improve pregnancy rates in PCOS patients in their clinical practices.