High stress levels can damage a woman's chances of getting pregnant, researchers warn. Those who are anxious are 12 per cent less likely to conceive during their fertile time than those who stay calm. It is the first proof that stress makes it less likely a woman will fall pregnant, despite long-standing anecdotal evidence that being relaxed can improve the chances.
Although the fall in success rates appears small, experts claim it can make a big difference to older women trying to have a baby when their fertility is naturally declining because of age.
In a study at Oxford University and the U.S. National Institutes of Health, blood levels of a marker for a stress hormone called alphaamylase were consistently higher in women who had trouble conceiving.
Dr Cecilia Pyper, from the National Perinatal Epidemiology Unit at Oxford University, said: 'This is the first study to find that a biological measure of stress is associated with a woman's chances of becoming pregnant-that month.
'We found that those women with high levels of a marker for stress were less likely to succeed in conceiving. 'The findings support the idea that couples should aim to stay as relaxed as they can about trying for a baby.
'In some people's cases, it might be relevant to look at relaxation techniques, counselling and even approaches like yoga and meditation. 'Many couples are very keen to know what they should do to improve their chances of conceiving and having a healthy baby, and this will help us provide the best advice.'
The researchers, who published their findings in the journal Fertility and Sterility, carried out saliva tests on 274 women aged 18 and 40 who were all planning pregnancy but not tried for more than three months.
They analysed levels of the stress hormone cortisol and the enzyme alpha-amylase, which is a marker for adrenalin - the 'fight or flight' hormone. Researchers carried out the tests on day six of each woman's menstrual cycle for a total of six cycles or until the woman fell pregnant. They used fertility monitors to identify ovulation and confirmed the pregnancies with testing kits.
The study found no effect from cortisol on the chances of falling pregnant. But women in the group with the highest levels of alpha-amylase had a 12 per cent lower chance of becoming pregnant for each day of their most fertile days than those with the lowest levels of alpha-amylase.
The researchers said: 'Irrespective of the day or frequency of sexual intercourse during the fertile window, women with higher concentrations of alpha-amylse were less likely to conceive than women with lower concentrations.
'Stress significantly reduced the probability of conception each day during the fertile window.' Dr Pyper said it was unclear how the stress hormone affected fertility, although it might reduce blood flow in the fallopian tubes which could affect transportation of the egg or sperm.
She said previous research appears to have focused on the stress hormone cortisol, rather than alpha-amylase, which may explain why it has been difficult to prove a link with fertility chances until now.
'The difference in your chances of getting pregnant could be important to older women in their late 30s trying for a first baby, or even a second or third child, at a time when their fertility is declining because of their age and it all takes longer,' she added. Dr Pyper said women were highly likely to benefit from relaxation techniques, particularly as such therapies had been shown to improve IVF pregnancy rates.
Leading fertility specialist Dr Allan Pacey described the findings as 'intriguing'. 'It's important for women to relax when they are trying to have a baby, but it's easier said than done,' he said. 'My advice to couples is to throw away the fertility charts and don't make trying for a baby a chore - it will stress you both out.'
Article: 12th August 2010 www.dailymail.co.uk