Clomiphene citrate in an in vitro fertilization program: hormonal comparisons between 50- and 150-mg daily dosages.

When clomiphene citrate is used for enhanced follicular recruitment in an in vitro fertilization and embryo transfer program, the usual dosage is 150 mg/day, although we recently reported comparable follicular development (size and number) with 50 mg/day. The present report compares circulating hormone levels between groups of patients receiving the two regimens. Gonadotropin levels were higher in the 150-mg group throughout the follicular phase. Serum estradiol (E2) levels, expressed either as total E2 or E2 per follicle greater than or equal to 15 mm, were also higher throughout the follicular phase in the 150-mg group. During the luteal phase, the progesterone levels were similar in both groups. However, there were higher E2 levels in the 150-mg group during the entire luteal phase. Even though there were no significant differences between groups with regard to the degree of enhanced follicular recruitment, there were significant differences in the observed hormone levels.