The menopause is defined as the time of the final episode of menstruation. It can therefore only be diagnosed with certainty in retrospect. The usual criterion is secondary amenorrhoea of at least 12 months duration in a woman more than 50 years old. After the menopause concentrations gonadotropins (FSH and LH) are raised and oestradiol is low. However, there may be marked disparity of clinical and hormonal status in the year before and year after the menopause.
The menopause is associated with exhaustion of the supply of follicles in the ovary and is preceded by a transitional phase often referred to as the perimenopause. This may take place over several years, or in some women, may not occur at all. During this time ovulation and menstruation occur at irregular intervals. Hormonal measurement during this time show the usual monthly cycles but as the ovaries become less responsive there is a gradual rise in the mean FSH concentration which can be seen after the age of 40 years. FSH values may rise to post-menopausal values during individual non-ovulatory cycles. It is therefore difficult to be certain whether the menopause has been reached from analysis of a single sample of blood.
Has the patient reached the menopause? This can only be diagnosed in retrospect (see above) but a repeat measurement of FSH at an interval of 3 months should help establish the diagnosis and provide information on any progress towards the menopause. Blood sample should, if possible be taken on the same day of the cycle.
This patient appears to be in the perimenopausal state; does she need to continue contraceptive measures in order to avoid conception? Perimenopausal women may ovulate irregularly until the menopause. Hormone levels offer no secure guide for contraceptive advice.
This patient appears to be in the perimenopause state; does she need hormone replacement therapy? Therapy with HRT should be given on clinical grounds for symptom control.