All women who live beyond the age of 55 to 60 years, and many of a younger age, experience a period of transition from the reproductive to the nonreproductive stage of life, of which the most striking feature is the permanent cessation of menstruation. Spontaneous menopause is the result of loss of ovarian follicular function. Because the permanent cessation of menstruation in over 90% of Caucasian women aged more than 45 years is preceded by the occurrence of amenorrhoea for 12 months, this interval is customarily used to indicate the fact that the menopause has occurred. In essence, menopause signifies the conclusion of a women's ability to conceive and bear children.
The human female is the only animal to experience menopause, which usually occurs between the ages of forty-eight and fifty-two. The occurrence and the severity of perimenopausal symptoms may well be affected by cultural and socioeconomic factors. The following factors are of possible relevance: the social significance of menstruation and the escape from the stigma of menstruation that follows menopause in some cultures; the social significance of childlessness; the social status of the postmenopausal woman; attitudes of husbands to their postmenopausal wives (for example, as a sexual partner); the level of socioeconomic deprivation experienced at the time; the degree of change in a woman's role at this time and the availability of new or alternative roles; the availability of medical help for perimenopausal problems. As yet, there are few studies comparing attitudes and reactions to the menopause in different cultures. Those that are available indicate that while the differences may be striking, their origins may be complex. For example, women from a particular (and relatively affluent) Indian caste reported fewer perimenopausal complaints than women in the USA. This could be attributed to the contrast in the status of postmenopausal women in the two cultures, the Indian women escaping from many earlier limitations and gaining higher social status, the American women anticipating loss of status in a 'youth-oriented' society.
There is at present controversy about whether there is a menopausal syndrome of somatic and psychological symptoms and illness, and there are virtually no data on the age distribution of the menopause and no information on its sociocultural significance in the developing countries. The subject of risks and benefits of oestrogen therapy in peri- and postmenopausal women is of considerable importance in view of the large number of prescriptions issued for such medicaments in developed countries, which indicates their frequent use, and the different interpretations and opinions among epidemiologists and clinicians on both past and current studies on this subject. The choice of family planning methods presents particular problems for women who are approaching the menopause, as well as the health repercussions of cessation of reproductive function and those caused by the agents used to treat the accompanying symptoms. By the year 2000, the average life expectancy for women in developed countries is expected to be 75 to 80, and in developing countries 65 to 70 years. The proportion of those reaching the age of 65 can be estimated at close to 90% in the developed and 70% in the developing countries; in the latter, one out of three of this group of over-65s can be expected to celebrate her eightieth birthday, compared with one out of seven under the mortality conditions of 1975. Life expectancy for women averages six years more than for men, at least in the developed countries. If it is assumed that reproductive function in women generally ceases at about the age of 50 years, it may be calculated that - by the year 2000 - one in every two to three of these women can expect about 30 years of post-menopausal life.