Post-pill amenorrhea: a causal study.

The distribution of distinguishable disorders in 102 patients with post-pill amenorrhea has been compared with that in 166 other patients with secondary amenorrhea, including 123 patients who had never used oral conception. In the post-pill group there was a 13% to 21% excess of patients who had a functional disorder without any weight loss or psychological disturbance to account for it and who typically were estrogenized and demonstrated intact feedback systems by their ovulatory response to clomiphene (the so-called cycle initiation defect). This excess might be explained by biased selection of oral contraception, but it seems wiser to assume a causal relationship, which amounts to a true risk of post-pill amenorrhea in less than 1 per 1000 users. No risk was revealed of primary ovarian failure, hyperprolactinemia, or pituitary tumor.