Drinking fewer than 14 servings of alcohol per week does not affect female fertility, according to a new study.
The results, published in the BMJ, provide evidence for the extent to which alcohol affects female fertility. Official guidelines in several countries, including the UK, USA and Denmark, recommend women trying to conceive should abstain from alcohol. However, current evidence has been unclear.
A team of researchers looked at the drinking habits of 6120 Danish women between 21 to 45 years old. All women were trying to conceive while in a stable relationship with a male partner, and were not receiving fertility treatment. Each participant completed a bi-monthly questionnaire for 12 months, or until conception occurred. The research was carried out between June 2007 and January 2016.
The results showed that type of alcohol consumed had no discernible effect. Women who drank more than 14 servings per week had an 18 percent lower chance of getting pregnant. One serving is the equivalent of around 120 ml of wine, one bottle of beer, or one shot of spirits.
However, the researchers caution that this is an approximate estimate as only 1.2 percent of women consumed over 14 servings of alcohol a week.
The study also did not distinguish between regular and 'binge drinking', which is known to be able to affect the menstrual cycle, nor take into account the alcohol intake of male partners, as heavy alcohol intake can affect sperm quality.
In a linked editorial to the study, Dr Annie Britton of University College London said that the results showed that 'total abstinence may not be necessary to maximise conception rates' for couples trying to get pregnant. 'However, it would be wise to avoid binge drinking, both for the potential disruption to menstrual cycles and also for the potential harm to a baby during early pregnancy.'
Dr Simon Fishel, managing director of CARE Fertility, pointed out the study did not take miscarriage or health of the conception into account. He also suggested that alcohol consumption could still exacerbate fertility issues for women who are struggling to conceive.
As this was an observational study, the biological mechanisms underpinning the impact of heavy drinking on female fertility are still unknown.