Drinking three small glasses of wine a week could reduce a woman's chances of conceiving by two thirds, research has found.
Government advice recommends that women trying to get pregnant should drink no more than 1 to 2 units of alcohol twice a week.
12:01AM BST 18 Oct 2013
The study of women's drinking habits in the months before they began fertility treatment found
that even low quantities of alcohol had a dramatic impact on the ability to conceive.
Research on couples who had already undergone around three failed cycles of IVF, found that women who abstained from all alcohol had a 90 per cent chance of achieving a successful pregnancy, over three years.
However, women who drank an average of just three small glasses of wine a week had a 30 percent chance of conceiving over the same period.
Researchers said the same patterns were likely to hold true for couples trying to conceive naturally.
The study found that even women who drank just one or two glasses of wine a week – well
within Government safe drinking limits for those trying to conceive - drastically jeopardised
their fertility, with success rates of 66 per cent.
Government advice recommends that women trying to get pregnant should drink no more than 1 to 2 units of alcohol twice a week - the equivalent of up to two glasses of wine.
Researchers who led the study of 90 women, presented at the American Society for Reproductive Medicine's annual conference in Boston, US, said it was not clear why relatively small quantities of alcohol had such an impact.
Lead author Dara Godfrey, an IVF specialist from Reproductive Medicine Associates of New York, said: "My advice to patients is always to limit or abstain from alcohol. But whether they do or not its up to them. Alcohol definitely has a detrimental effect on pregnancy success."
Dr Godfrey said the same impact was likely to occur in women trying to conceive naturally, with the greatest effect likely to be felt among those who had several drinks on the same evening.
She said researchers had not identified the mechanism which meant alcohol reduced fertility, but that it was possible it jeopardises normal egg development.
Some fertility clinics recommend that clinics stop drinking for three months before they start IVF treatment, because it takes that long for an egg to develop.
Dr Allan Pacey, a fertility expert at the University of Sheffield said the differences in pregnancy rates between the groups were substantial, and consistent with advice to avoid alcohol if trying to conceive.
However, he said it was possible that there were other differences between the women who abstained from alcohol entirely, and those who had several drinks a week.
Dr Pacey said: "I would wonder whether alcohol could be a surrogacy marker for something else - that the women who have something to drink are more likely to be stressed."
Stress levels affect hormones such as cortisol which can interfere with reproductive cycles.
The university's research on sperm quality last year suggested that moderate intake of alcohol did not affect male fertility, he said.
"There is a certainly a bit of a difficulty in advising men that it is okay for them to drink if trying to conceive but women shouldn't touch a drop - that could create tensions in many a household," he said.
Laura Donnelly, Health Correspondent