Exogenous estrogen therapy for treatment of clomiphene citrate-induced cervical mucus abnormalities: is it effective?

Clomiphene citrate (CC) may have an adverse effect on cervical mucus (CM) quality and quantity. A placebo-controlled study was performed to assess the effect of exogenous follicular phase estrogen (E) on CM. Subjects qualified for inclusion by repeated demonstration of poor CM while on CC therapy as judged by spinnbarkeit, quantity, and viscosity. Subjects were treated by a randomized, placebo-controlled format using: (1) oral micronized estradiol (E2), 2 mg; (2) conjugated Es, 5 mg, or (3) placebo administered on cycle days 9 to 14. Cervical mucus was scored blindly during therapy within 48 hours before ovulation. Twelve subjects were observed through 36 treatment cycles with mean (+/- SD) CM scores: micronized E2, 4.2 +/- 1.8; conjugated Es, 4.3 +/- 1.7; and placebo, 4.7 +/- 2.9. There was no significant difference in mean values (P = 0.96, analysis of variance) or frequency of CM score greater than 4 (P = 0.85, Fisher exact test). We conclude that therapy with the E preparations tested did not improve the quality or quantity of CM in CC-treated patients.