Assessment of ovarian function in perimenopausal women after stopping oral contraceptives.

Ovarian function was assessed by measuring plasma gonadotrophins, urinary oestrogen and urinary pregnanediol levels, every week for four weeks, in 34 women, aged 45 to 57 years, after withdrawal of oral contraceptive therapy. A rise in urinary pregnanediol excretion occurred in 14 patients suggesting that ovulation had occurred and that these patients were "premenopausal". Elevated serum gonadotrophin values and persistently low urinary oestrogen and pregnanediol excretion occurred in 13 patients suggesting ovarian failure or a "postmenopausal" state. However, one apparently "postmenopausal" patient later showed hormonal evidence of ovulation, indicating fluctuation in ovarian function. There were 7 patients with "indeterminate" hormone profiles whose ovarian function was difficult to assess. All patients excreting more than 45 nmol of oestrogen a day had a spontaneous period within 45 days of stopping hormone therapy.