Chronic low-dose follicle-stimulating hormone compared with clomiphene human menopausal gonadotropin for induction of ovulation

Concurrent administration of clomiphene can reduce the amount of gonadotropins required for induction of ovulation. Recently, follicle-stimulating hormone (FSH) administered in a chronic, low-dose fashion has been reported to give satisfactory pregnancy rates. We compared the conventional clomiphene/human menopausal gonadotropin (hMG) with the chronic, low-dose FSH regimen for induction of ovulation in 87 patients over 110 cycles. The clomiphene/hMG regimen required half the amount of gonadotropin compared to the chronic FSH regimen to achieve follicular maturation. Despite the reduced amount of gonadotropin, the clomiphene/hMG regimen induced a mean fourfold higher level of estradiol production and was associated with significantly greater numbers of large and intermediate-sized follicles compared to the chronic FSH regimen. The proportion of clomiphene/hMG cases with multifollicular development and overstimulation was therefore high (30%). In contrast, the chronic FSH regimen, despite requiring larger amounts of gonadotropin and longer periods of treatment, resulted in unifollicular development, low rates of overstimulation and improved pregnancy rates. We conclude that although clomiphene can reduce the requirement for gonadotropins, the relative safety and effectiveness of the chronic low-dose FSH regimen makes it the method of choice for ovulation induction.