Time of initiation of clomiphene citrate and pregnancy rate in polycystic ovarian syndrome.

OBJECTIVE

To investigate whether the timing of clomiphene citrate (CC) administration affects hormonal levels, follicular growth, endometrial thickness, and ovulation and pregnancy rates in women with polycystic ovarian syndrome (PCOS).

METHODS

Of the 78 infertile women with PCOS who participated in this prospective, double-blind, randomized clinical trial, 37 collectively underwent 71 cycles of CC (100 mg/day) on days 1 through 5 of the menstrual cycle (group 1) and 41 collectively underwent 73 cycles of CC at the same concentration on days 5 through 9 (group 2). Hormonal levels, follicular growth, endometrial thickness, and ovulation and pregnancy rates were compared.

RESULTS

The mean number of follicles and the maximum follicular size were greater in group 2. However, ovulation rates were 72.8% in group 1 and 70.8% in group 2 (P=.78), and pregnancy rates were 40.5% in group 1 and 19.5% in group 2 (P=.04).

CONCLUSION

Treatment with CC is associated with higher rates of pregnancy if started early (days 1-5) in the menstrual cycle.