Is it all right for women to drink small amounts of alcohol in pregnancy? Yes

Abstract

The National Institute for Health and Clinical Excellence draft guidance on drinking during pregnancy has added to confusion about safety. Pat O'Brien believes that telling women to abstain is overly paternalistic on current evidence, but Vivienne Nathanson and colleagues argue that this is the safest message

Until May of this year, the Department of Health advised pregnant women in England not to drink “more than one to two units of alcohol once or twice a week.” Since then, both the department and the British Medical Association have changed their stance;^{1 2} pregnant women are now told to avoid alcohol completely. There is no new evidence so why the change?

Fetal alcohol syndrome is a serious condition and is clearly a consequence of heavy alcohol intake during pregnancy.³ Although rare (128 cases in England in 2002-3), it is the leading cause of non-genetic intellectual disability in the Western world. The incidence of the broader range of fetal alcohol spectrum disorders is more difficult to determine, for various reasons, including difficulty in diagnosis, under-reporting, and confounding.⁴

State of evidence

Nevertheless, there is still no evidence that low to moderate alcohol intake in pregnancy has any long term adverse effects. But don't take my word for it. Last year the Royal College of Obstetricians and Gynaecologists concluded a comprehensive analysis with the view that “There is no evidence of harm from low levels of alcohol consumption, defined as no more than one or two units of alcohol once or twice a week.”⁵ In 2003, the Midwife Information and Resource Service updated their evidence based advice: “Women can be reassured that light infrequent drinking constitutes no risk to their baby.” The Medical Council on Alcohol reached a similar conclusion,⁶ and a report in 2006 from the National Perinatal Epidemiology Unit in Oxford found “no consistent evidence of adverse health effects from low-to-moderate prenatal alcohol exposure,” although it did add that the current evidence is not robust enough to rule out the possibility completely.³ The most recent review, published in September 2007 in draft form by the National Institute for Health and Clinical Excellence advises that, based on current evidence “pregnant women should limit their alcohol intake to less than one standard drink (1.5 UK units or 12 g of alcohol) per day and if possible avoid alcohol in the first three months of pregnancy. It would appear that drinking no more than 1.5 units per day is not associated with harm to the baby.”⁷

So, no evidence of harm from low levels of intake in pregnancy, but we can't completely exclude the possibility. But in a sense, all of this is of secondary importance. I'm not trying to argue that low levels of alcohol are definitely safe. What I am arguing is that we should respect the autonomy of pregnant women. We have a duty to be open and honest with the people we advise. Women are entitled to decide for themselves (and their babies); some are more risk averse than others and will wish to abstain completely. Indeed, even with the previous advice, around half of all women abstained during pregnancy.

So why has the stance of the government and the BMA changed when the evidence has not? Quite rightly, there is widespread concern about the rise in heavy drinking by young people, particularly women, in Britain over the past decade.² Over a third of women in their 20s have engaged in binge drinking. The BMA believes that “this will lead to an increased risk of heavy drinking during pregnancy and subsequently an increased risk of having a baby who is affected by prenatal alcohol exposure.”² The Department of Health disagrees, stating recently that “most women do actually stop drinking or drink very little in pregnancy.” However, the department found that 9% of pregnant women drank more than the recommended limit—clearly a cause for concern. The reasons given for the changed advice are that there is confusion, the advice is unclear, and people don't understand what is meant by a unit of alcohol.

Ban is unhelpful

I disagree with the solution. If we in the medical and midwifery professions have failed to communicate clearly to women the meaning of safe limits, then we need to put this right—not take the easy option (for us) and ban alcohol completely. Where is the evidence that this new advice will change the behaviour of the 9% who currently drink more than the recommended safe limit? In fact, in the US, where the surgeon general has since 1981 advised the complete avoidance of alcohol in pregnancy, and all alcohol containing products carry a health warning, the incidence of frequent drinking in pregnancy rose from 0.9% in 1991 to 3.5% in 1999.

Are there any potential disadvantages to a complete ban? Well, yes—I believe there are. Firstly, the strong advice not to drink implies a certainty and confidence in the evidence that simply does not exist. There is a danger that our stance is perceived as paternalistic and will lead to a loss of confidence in medical advice in general. Secondly, I have already seen how it has frightened women who followed the safe limit advice earlier in their pregnancy or in a previous pregnancy, only to be told now that this was potentially harmful. Thirdly, it is also likely to increase under-reporting of alcohol consumption in pregnancy. As the BMA points out: “monitoring maternal alcohol consumption is [already] complicated by [the fact that] women feel afraid and embarrassed to admit they are drinking during pregnancy.”² This fear and embarrassment can only increase as a result of this new advice.

So, in fact, I reject not just the motion, but also its underlying premise. It is no longer our role, having acknowledged our lack of evidence in this area, to make a value judgment (for that is what it is—not a medical judgment) on behalf of our patients, let alone healthy pregnant women. On the basis of the evidence we provide, many women will choose abstinence as the safest option. But that choice is the right of each individual woman.