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Moderate drinking does not appear to affect a woman's fertility, according to new research.

A study looked at the alcohol drinking habits of more than 6,100 Danish women aged between 21 and 45 years old, between June 2007 and January.

It found consuming less than 14 "servings" a week seemed to have no discernible effect on fertility, compared with women not drinking.

But Prof Simon Fishel said the study did not take into account miscarriages.

One in six couples in the UK struggles to conceive, making fertility concerns one of the most common reasons women visit their GP.

Vulnerable

In the UK the current guidance on alcohol, as endorsed by the Department of Health, says that "if you are pregnant or planning a pregnancy, the safest approach is not to drink alcohol at all, to keep risks to your baby to a minimum".

Fertility treatment 'works for most'

The authors of the Danish study, published in the British Medical Journal, agree with this advice and recommend couples to abstain from alcohol during their fertile window until a pregnancy is ruled out, because the foetus may be particularly vulnerable to alcohol during the first few weeks following conception.

The study assessed overall alcohol consumption as well as intake of specific types of alcoholic beverages, including beer, wine, and spirits.

Alcohol consumption was self reported and one serving of beer was measured as a 330ml bottle, while red or white wine was a 120ml glass, dessert wine was a 50ml serving and spirits were categorised as 20ml.

Each female participant completed a bi-monthly questionnaire for 12 months, or until conception occurred, on alcohol use, pregnancy status, menstrual cycles, frequency of intercourse, and smoking.

'Difficulty conceiving'

Women who drank more than 14 servings a week had an 18% lower chance of getting pregnant, the study suggested.

This is an observational study, and so the research cannot arise at any firm conclusions.

However, in a linked editorial, Annie Britton from University College London, said that the results "offer some reassurances" to couples trying to get pregnant.

She suggests that "total abstinence may not be necessary to maximise conception rates" because "if alcohol is consumed moderately, it seems that this may not affect fertility".

"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. If a couple are experiencing difficulty in conceiving, it makes sense for both partners to cut down on their alcohol intake," she said.

Common causes of infertility

Women:

damage to the fallopian tubes

ovulatory problems

endometriosis

age

polycystic ovary syndrome

diabetes

being overweight or underweight

smoking

Men:

low sperm count

problems with the tubes carrying sperm

problems getting an erection or ejaculating

diabetes

being overweight

Source: HFEA

But Prof Simon Fishel, who is the managing director Care Fertility, said that while the sample size of the study was large and it showed "excellent statistical methods" we must not confuse a healthy pregnancy with the ability to conceive.

"The study implies that with up to 14 'servings' per week the chance of conceiving was no different from those who did not consume alcohol.

"However, as the study ended at a home pregnancy test, no measure of miscarriage or even the presence of a foetal heart was reported, giving no insight into the health of the conception."

He also said that the study said nothing about those who may be struggling to conceive, for whom alcohol intake may "exacerbate a sub-fertile condition".

'Steady as she goes'

However, Prof Darren Griffin at the University of Kent said the overwhelming message of the study was "steady as she goes".

He said: "If you do drink while trying to have children, do it in moderation and don't binge drink. One might argue that this should be a maxim for life in general.

"The Danish study is robust and well conducted, it is also refreshingly aware of its own limitations, such as that alcohol intake is self-reported - and thus may be under-reported - and the effect of alcohol consumption on the male partner is not measured.

"One interesting finding is that, although some previous studies have reported a positive effect of moderate drinking on fertility, this current study found no such association."