Incidence of ovulation in perimenopausal women before and during hormone replacement therapy.

Once hormone replacement therapy (HRT) has been commenced, it becomes extremely difficult to advise women approaching the menopause on the need for contraception. In this study of twenty women, neither the regularity of their pre-existing menstrual cycle nor a random FSH concentration predicted the likelihood of subsequent ovulation whilst taking HRT. HRT is not reliably contraceptive and women commencing HRT whilst still menstruating spontaneously must be advised on the need for additional contraception.