TORONTO -- Metformin is often the only drug needed to achieve ovulation and conception in patients with polycystic ovary syndrome, according to a study presented at the annual meeting of the Society for Gynecologic Investigation.
And even patients who require additional therapy with clomiphene citrate often need only small doses, said Dr. Michael Heard, a fellow in reproductive endocrinology at the Baylor College of Medicine, Houston.
"Often PCOS [polycystic ovary syndrome] patients have failed many previous attempts to get pregnant, including high doses of clomiphene citrate and in vitro fertilization. When you think of the emotional and financial cost of this, our study is good news," Dr. Heard said.
Merformin is an oral hypoglycemic drug used primarily in the treatment of diabetes. In PCOS patients, the drug has been shown to induce regular menses and ovulation; correct hyperinsulinemia, which is believed to play a role in the pathogenesis of PCOS; and reduce levels of luteinizing hormone, sex hormone --binding globulin, and ovarian androgens.
This study is one of the first to look at conception rates and time to conception for PCOS patients on metformin, he said in an interview.
A total of 49 oligomenorrheic patients with PCOS entered the study, many of them having failed multiple previous cycles on clomiphene. They were initially treated with 500 mg of metformin twice a day for a period of 6 weeks, Dr. Heard added.
If their menses resumed, ovulation was monitored and intercourse was timed using basal body temperature.
If menses or ovulation did not resume, the metformin dose was increased to 500 mg three times a day.
And if there was still no response after another 6 weeks, 5 days of clomiphene (50 mg/day) was added.
Following this treatment protocol, 27 patients (55%) resumed menses and showed evidence of ovulation, with 18 patients responding with metformin alone and another 9 patients responding with metformin plus clomiphene.
Nineteen of the patients (38.8%) conceived; the median time to conception was 3 months.
"PCOS patients can be told that if they are cycling normally after metformin therapy their chances of getting pregnant increase significantly, regardless of what their history has been," Dr. Heard commented.
"At entry into this study, roughly 70% of our patients were Clomid resistant, but with metformin, many ovulated alone, and when we had to give Clomid it was the lowest dose," he said.
Patients were kept on metformin therapy through 12 weeks' gestation. However, 7 of the 19 pregnancies (37%) ended in spontaneous abortion.
In addition, 40% of the study subjects had gastrointestinal side effects, including diarrhea, abdominal cramping, and nausea. This, however, did not adversely affect overall patient compliance.
COPYRIGHT 2001 International Medical News Group
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