The effect of clomiphene citrate treatment on cervical mucus and plasma estradiol and progesterone levels.
OBJECTIVES: To study the relationship between cervical mucus (CM) quality, postcoital test (PCT) results and plasma estradiol (E2) in clomiphene citrate (CC)-treated women. A subsidiary aim was to study the relationship between CM quality and plasma progesterone (P). DESIGN: Untreated women were compared with oligo-ovulatory patients given CC. SETTING: Infertility Clinic, Fazakerley Hospital, United Kingdom. PATIENTS, PARTICIPANTS: Fifty-one untreated patients and 31 women given CC. INTERVENTIONS: The treated women were given 50 mg/d CC from days 2 to 6 of their cycle. MAIN OUTCOME MEASURES: A CM assessment, a PCT, plasma E2, and P were performed at the anticipated time of ovulation based on at least two previous basal body temperature charts and menstrual patterns. RESULTS: In untreated women there was a very strong tendency for CM quality to improve with rising plasma E2 levels and to worsen with rising plasma P levels. There was a significant association between CM quality and PCT results. Similar results were found in CC-treated women, except that plasma E2 was very significantly higher and there was a significant inverse relationship between plasma E2 and CM quality. CONCLUSION: High plasma E2 in the periovulatory phase in CC-treated women is a marker for increased sensitivity to and continuing action of the antiestrogen. This impairs the quality of the CM.