Stress has already been blamed as a cause of miscarriage and infertility this year. And only last month, at an international fertility conference in Prague, stress was claimed to make IVF fail. Stress in pregnancy was linked last year to attention deficit hyperactivity disorder (ADHD) in children and premature delivery. And all of this is on top of what stress is said to do to women’s cycles and memories.
Whatever stage women are at in their lives, stress seems to be the all-pervasive baddie. It’s all very, well, stressful. So what’s the evidence and should women be downsizing and taking up yoga to preserve their fertility and sanity? And at what point in their lives should they be most concerned? Defining what constitutes stress is the first problem. So-called metabolic stressors (lack of food, heat, cold, prolonged physical activity, infection) have a near universal stressing effect, but how about commuting, failing relationships, money worries, long hours, bullying?
But what stresses you could be all of these or none of them; what saps one woman may energise another. You should also be wary of seeing the word “stress” in a news report and then applying it to your life. For instance, a miscarriage study published in the Proceedings of the National Academy of Sciences in March this year, which linked higher levels of cortisol (the stress hormone) with miscarriage, was carried out in Guatemala among women who lived in grinding poverty, many of whom often went hungry. That’s not Times readers. And is the asumption that women are more vulnerable to stress than men even correct?
Depression and post-traumatic stress disorder (PTSD) are twice as common in women as in men. But in a key paper on female civil servants and psychological problems, Professor Rachel Jenkins showed that when you adjusted for different jobs and social position, the differences between men and women disappeared.
Professor Simon Wessely, a psychiatrist at King’s College London, points out that this study suggests very strongly that differing biology is not to blame. “The main reason for the undeniable higher rates of stress in women was related to their different roles and pressures, but when men and women did the same job in the Civil Service, they had similar rates of psychological problems, ” he says.
However, there is another reason for thinking that women are more vulnerable. Reproduction is sensitive to stress, a biological adaptation that prevents us having babies when times are hard. Only women have a visible sign of their fertility, their periods, and they notice when they are late or disappear, which can often be stressinduced. But the equivalent stress effect in men — a reduction in sperm count — is unseen. Only when men fail to conceive do they visit a doctor. In fact, when US army researchers studied the effects of a double stress (no food combined with a complex war drill) on men and women, it was the men whose reproductive hormone function was the more profoundly depressed.
Nevertheless, there are key points in women’s lives when their biology makes them vulnerable to stress, especially at times of hormonal turmoil:
STRESS AND PERIODS
Your brain makes a call as to when pregnancy would be a bad idea based on indicators such as the level of body fat (hence period loss in athletes and those with anorexia) and levels of stress. It then implements its decision through alterations in hormone levels. Women’s periods may thus go haywire after trauma, for example, moving away from home or during exams. Equally, and less well-known, is the erotic stress effect in which the brain sneakily rearranges cycle length to make pregnancy more likely when there is a hot man in your life. Beware.
STRESS IN YOUR THIRTIES
Stressed women in their thirties are often surprised to develop spots for the first time since their teens. When women are stressed it causes a rise in circulating levels of androgens (male hormones), to which the skin is particularly sensitive, resulting in pimples and greasy skin.
STRESS AND FERTILITY
We all know couples who have been trying in vain for a baby only to fall pregnant after a relaxing holiday. The immediate conclusion is that stress must have been the cause. But pregnancy is a function of two things: length of time trying and opportunity. Holidays are when the two things may finally coincide. How else do you spend the time between sunbathing and dinner? At the recent European Society of Human Reproduction and Embryology conference in Prague, Professor Sancha Berga, of Emory University, Atlanta, presented the results of a pilot study in which a talking therapy was used to reduce stress. It was successful in restoring ovulation in six out of eight women who had had no periods for six months. This is an interesting finding but, in general, it is agreed that infertility results in stress rather than being caused by it.
“If you’ve been trying for a few years, stress is unlikely to be the cause of infertility,” says Laurence Shaw, the deputy medical director of the London Bridge Fertility Centre. As for stress as a reason for non-implantation, he points out that women regularly become pregnant after rape, which is as stressful a trauma as you get.
STRESS AND PREGNANCY
“There’s more and more evidence that stress in pregnancy causes a wide range of effects in the baby. It’s very strong,” says Vivette Glover, a professor of perinatal psychobiology at Imperial College. These effects include a higher incidence of premature delivery and of ADHD in children, as well as short concentration span.
Increased anxiety in a child is a biological adaptation that ensures that children likely to be born into stressful situations are more vigilant. In the short term, this may be life-saving, but it is at a cost of a shorter life span owing to an increased risk of premature heart disease.
But Professor Glover emphasises that not all women will be affected by stress, even if it is severe, and even in those that are affected, the vast majority of their babies are still perfectly healthy.
Pregnant women are, however, naturally protected from the effects of stress by progesterone, which is released in industrial quantities during pregnancy. It has a sedative effect — it can be used as an anaesthetic in large quantities — protecting women and their babies from the effects of stressors in pregnancy and resulting in the cow-like tranquillity of pregnant women.
STRESS AND THE MENOPAUSE
Women often report the menopause years as stressful. Certainly the stress system is affected by changing reproductive hormone levels during menopause. A rise in cortisol occurs with age, while the levels of male hormones (androgens) also rise. It makes depression more likely.
Women may also find it more difficult to deal with stress, although taking HRT improves the ability of women to complete stressful tasks under laboratory conditions.
The final enigma about women and stress is this: when men are faced with stressful situations, a rise in testosterone tends to produce aggression. Women under stress produce oxytocin, the hormone of bonding, which leads stressed women to “tend and befriend” in moments of anxiety. Our bodies are geared to cope with stress. Don’t let it stress you out.
WHAT IS STRESS?
When we are stressed the adrenal glands, situated on top of the kidneys, release two sorts of hormones involved in the stress response. The “fight or flight” hormones, adrenalin and nor-adrenalin, are released almost instantaneously and prime the body for immediate action. Cortisol is also released but acts more slowly, mobilising energy stores to keep the body at peak performance for a longer period of time.
