Deteriorated quality of cervical mucus under the influence of clomiphene: A meta-analysis

Objective. To determine whether clomiphene (citrate) has a negative influence on cervical mucus qualities and whether administration of exogenous oestrogens has a favourable influence in that case. Design. Meta-analysis. Setting. Stichting Gezondheidszorg Oostelijk Zuid-Limburg, Midwifery School, Kerkrade, the Netherlands. Method. Relevant articles were searched using the Medline database for the years 1980-1996 and the Knowledge Finder search system. The reference lists of these articles were studied. All prospective, randomized and controlled clinical trials mentioning detailed figures were selected and analysed. Results. Six articles met all criteria for analysis of the effect of clomiphene on cervical mucus. Clomiphene 50 mg/day had an unfavourable influence on cervical mucus (not significant), but clomiphene 100 and clomiphene 150 mg/day did have a significant effect, the relative risk of unfavourable cervical mucus being more than seven in comparison with women not using clomiphene (respective odds ratios 7.90 (95% confidence interval: 4.15-15.00) and 7.50 (1.97-28.60). Four articles met all criteria for analysis of the effect of exogenous oestrogens on cervical mucus of women being treated with clomiphene. Exogenous oestrogens resulted in improvement of the cervical mucus qualities in these women (odds ratio: 2.87 (1.76- 4.69)). Conclusion. The influence of clomiphene 50 mg/day on cervical mucus is not significantly unfavourable, unlike the influence of clomiphene 100 and 150 mg/day. Exogenous oestrogen administration improves this cervical mucus. In all patients being treated with clomiphene the cervical mucus qualities should be investigated.