Couples hoping to have a baby through in-vitro fertilisation (IVF) may want to watch their alcohol intake, if new research is correct.
Among more than 2,500 couples undergoing IVF, the odds of having a baby were somewhat lower among women who were drinking as few as four drinks per week when they began their IVF cycle. When both partners drank that much, the chances were lower still.
The findings, published in Obstetrics & Gynaecology, do not prove that alcohol was the reason for the lower IVF success rates. But they raise the possibility - which would mean there's something couples can do to influence their chances of having a baby, said lead researcher Dr Brooke V. Rossi, of Brigham and Women's Hospital in Boston.
"There are so many factors that patients have no control over - like their age or oestrogen levels. But they can change their drinking habits," Dr Rossi said in an interview.
She and her colleagues report that among women who said they currently had four or more drinks per week, 22% ultimately had a baby, compared to 27% of women who drank less or not at all.
After adjustment for age, weight, smoking habits and other factors, the higher drinking level was linked to 16% lower chances of IVF success.
There was no strong link between men's overall alcohol intake and IVF birth rates.
However, the researchers found that when both partners were having four or more drinks per week at the start of the IVF cycle, the couple was 21% less likely to have a baby, compared to couples who drank less.
Dr Rossi and her group can't explain their findings. However, they note that higher drinking levels, in both women and men, were linked to a greater risk of failed fertilisation.
According to her, the finding hints that alcohol might have its effects in the earliest stages of conception - though, if true, the precise reasons are unknown.
"I would encourage people to try to decrease, or even stop, drinking when they start IVF," she said.
Results are not clear
The researchers asked couples about their current drinking habits at only one time point - when they were first starting IVF. So it's not clear whether drinking in the weeks to months beforehand - or drinking at a particular point during the IVF process - are related to the odds of success.
Nor is it clear whether the findings have any relevance to couples trying to conceive naturally. "I can't make any recommendation on that, based on our data," Dr Rossi said.
When it comes to fertility in general, studies have reached conflicting conclusions about the possible role of alcohol. Some have suggested that women who drink moderately might have a harder time becoming pregnant than non-drinkers. Others, however, have found no such connection. (Reuters Health/ December 2010)
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