Relationship of clomiphene dose and patient weight to successful treatment

Our objective was to examine the relationship between patient weight andthe dose of clomiphene required for pregnancy so as to assess the validityof recommendations that the dose of clomiphene be limited to 100 mg. Weretrospectively analysed the weight-dose relationship in 1681 clomiphenepregnancies and the relationship between dose and pregnancy, births,multiple births, number of pre-ovulatory follicles and endometrialthickness in 2841 cycles of clomiphene treatment, 25- 250 mg, for 5 daysbefore intrauterine insemination (IUI). Doses of clomiphene >100 mg/daywere used before pregnancies in 27.4% of patients who weighed >90 kg andin 14.7% of all pregnancies. In IUI cycles, pregnancies and births, but notmultiple births or abortions, were related to dose. An increase in dosefrom 25 to 100 mg resulted in higher pregnancy and birth rates, and in anincrease in the average number of pre-ovulatory follicles > or =12 mm indiameter, from 2.0 to 2.8, with no additional increase at higher doses.Endometrial thickness and cycle day of insemination were not related todose. We conclude that doses of clomiphene may safely be increased beyond100 mg, and that doses > or =100 mg are required in significant numbersof patients.