For the one in seven UK couples struggling to conceive, the news that common treatments will do nothing to increase their chances will come as a blow. A report in the BMJ has suggested that fertility clinics should send patients home empty-handed after a study by Siladitya Bhattacharya, a professor of reproductive medicine at the University of Aberdeen, found that the fertility pill clomifene and intrauterine insemination (IUI) were no more effective than recommendations on when couples should have sex.

A frequent cause of infertility is not making love enough in the middle of the woman's cycle. There's no such thing as too much sex; last year an Australian study found that men with fertility problems could boost their sperm count by having sex every day. If that fails, IVF is an option, with a success rate of 21.6% across women of all ages, and 29.6% for those under 35. But changing your lifestyle can help too. Marilyn Glenville, author of Getting

Pregnant Faster recommends a diet rich in nuts, seeds and oily fish, which provide essential fatty acids that play a crucial role in fertility, and low in caffeine and simple carbohydrates.

There is clear evidence that being overweight or underweight affects a woman's chance of conceiving. Researchers at the University of Aberdeen have also found that obese men tend to have lower sperm quality because the fat around their testicles causes them to heat up.

Stress, too, can affect the production of reproductive hormones. This may partly explain why 17% of the couples who received no treatment in Bhattacharya's study fell pregnant despite failing to conceive for two and half years previously. On the point of giving up, their tension levels may have fallen only for Mother Nature to come up trumps.