SECOND OPINION:All women experience menopause at some stage, usually between 45 and 55 years of age. This marks the end of child-bearing and the start of the rest of their lives.
Menopause is an evolutionary puzzle because, apart from humans, pilot and killer whales are the only known species where females stop breeding relatively early in their lifespan. Most mammals become less fertile as they age and rarely survive beyond the point where their eggs run out, even in captivity. Humans and some whales are different because they carry on living long after the menopause.
Female killer whales reach menopause at age 50 and can live until they are 90. Female pilot whales stop breeding by age 36 and can live until 65.
A new study, published in the November issue of Ecology Letters, identifies a plausible reason for why women live many years after menopause. Using a 200-year-old data set of more than 14,000 people, researchers found that the need for older child-free women in human societies and reproductive conflict between in-laws may account for menopause in human females.
When grandmothers and daughters-in-law gave birth at the same time there was a 66 per cent reduction in offspring survival.
The evolutionary mechanism of natural selection meant that older women who stopped breeding when their daughters-in law began were more likely to survive and become important members of the tribe.
Child-free older women
The enhanced role of child-free older women brought distinct benefits to complex human societies. These women were free to be sources of wisdom, skills and cultural memory. Living for many years after menopause conferred benefits and status on older women and ensured the survival of the species.
The big question for women’s health in 2012 is how a natural phenomenon, which evolved over many millennia, became something to be regarded with apprehension, even dread, within one generation.
My mother gave birth to her last child at 46 and she looked forward to the “change” as a welcome release from the fear of pregnancy. Menopause meant freedom for women of my mother’s generation.
Over the past 50 years or so it has become an abnormality: something to be treated with hormone replacement therapy (HRT) or herbal remedies to prevent completely normal physical and emotional experiences.
It is not just drug companies and health food shops that make money from menopause. Walk into any bookshop and you will find shelves of self-help books on how to avoid, deny or defer these experiences as long as possible, if not forever. What has happened to menopause?
There is a reluctance to accept the reality of what happens before, during and after menopause, which can be summed up in two words: oestrogen withdrawal.
Like drug addicts, nearly 40 years of women’s lives are more or less controlled by very powerful hormones, which, like all mood-altering drugs, influence their emotions, physical health and relationships.
Cold turkey
When a woman’s ovaries are empty of eggs and she no longer needs high levels of oestrogen, her body stops producing it in such large quantities and withdrawal sets in. Experiences associated with oestrogen withdrawal, such as exhaustion, joint pain, hot flushes, cold sweats, anxiety and sleep disorders, are almost identical to those of withdrawal from other mood-altering drugs.
Taking HRT is like taking methadone for heroin addiction: it is not a solution and puts off the day when a woman has to go through the change anyway. She may as well go “cold turkey”.
Why do women bother taking HRT or herbal remedies?
The Cochrane Collaboration has produced several recent systematic reviews showing that HRT has negative long-term effects. There is no evidence that HRT provides any heart health benefits. Women taking HRT have a higher incidence of heart attacks, strokes and leg blood clots than women taking placebos.
Herbal treatments
There is no evidence that HRT has a positive effect on cognitive functioning, whether given as a short- or long-term therapy. There is no evidence that herbal treatments work any better. Black Cohosh is often recommended for oestrogen withdrawal and an October 2012 Cochrane study shows there is insufficient evidence to support its use.
There are more than 800,000 women over 45 living in Ireland, at least half of whom are using some form of HRT or taking herbal remedies. It is time to reclaim menopause as a great evolutionary breakthrough that confers huge benefits and status on 21st-century older women, not something to be feared and medicated away.
Dr JACKY JONESis a former HSE regional manager of health promotion