Luteal insufficiency: correlation between endometrial dating and integrated progesterone output in clomiphene citrate-induced cycles.

Midluteal phase endometrium was histologically dated with midcycle luteinizing hormone surge time in 29 cycles from 10 parous women during untreated cycles (control) and treatment with clomiphene citrate 50 mg and 150 mg daily on days 5 through 9. Integrated progesterone output for 7 days after luteinizing hormone surge calculated from the daily plasma progesterone levels was 66.6 +/- 9.8 ng/ml in the control group compared with 117.5 +/- 18.6 ng/ml for clomiphene citrate 50 mg treatment and 152.1 +/- 11 ng/ml for clomiphene citrate 150 mg treatment (p less than or equal to 0.05). Only one cycle (clomiphene citrate 150 mg) had an out-of-phase endometrium and a significantly reduced integrated progesterone output of 28 ng/ml. All other cycles showed synchronous endometrial maturation. We conclude that luteal insufficiency as a result of clomiphene citrate treatment in ovulatory women is infrequent and is more likely to be a result of functional outcome of a relative lack of luteal phase progesterone output.