Drinking in pregnancy: how should the guidance work?

Dr James Nicholls | May 2018 | 8 minutes

How should advice on alcohol and pregnancy be communicated?

This seems like a simple question: just tell expectant mothers what the science says, and suggest how they should act on that information. But a new study, funded by Alcohol Concern Cymru, has found that the reality is more complex.

We know that heavy drinking in pregnancy is extremely risky; it can lead to devastating impacts on the child which last for their lifetime. Foetal alcohol syndrome is a condition that affects both physical and brain development, and is associated with a range of problems in adulthood including higher rates of imprisonment and unemployment. We also know that these problems range in severity, and that these conditions (known as Foetal Alcohol Spectrum Disorders, or FASDs) are often undiagnosed, or not recognised until later in life. In reality, we don’t know the exact level of foetal alcohol disorders in the population. And we don’t know how much a pregnant mother has to drink before risk becomes significant.

Because of these uncertainties and the potential severity of FASDs, from 2016 onwards the Chief Medical Officers (CMOs) have recommended that people who are pregnant should not drink at all. So: the low-risk drinking guidelines are based on the ‘precautionary principle’ that because we don’t know exactly how much alcohol is linked to increased risk, the safest option for mothers-to-be is not to drink at all.

At first glance, that sounds sensible enough. So why isn’t it that straightforward?

Balancing the risk: alcohol vs anxiety

The science on the impact of low levels of alcohol consumption (up to around four units a week) on pregnant women and their babies is weak. Two systematic reviews (here and here) come to the similar conclusion that, as it stands, there is no strong evidence that drinking at low levels is harmful. This is partly a case of absence of evidence (i.e. drinking even at low levels might be harmful, but we just haven’t been able to show it yet). But it is not just a lack of evidence, because the research we do have tends to suggest few risks at this level.

The CMOs want to give clear advice that’s easy to follow (“don’t drink at all”), but this advice can create anxiety, especially for mothers who drank in the early stages of their pregnancy, before realising that they were expecting. Any advice given needs to balance the risks of alcohol with the risk of anxiety, especially as anxiety in pregnancy is also a risk factor.


These are the kinds of issues addressed in this new study. Participants, including mothers, midwives, antenatal teachers and policy-makers, were clearly aware that there are balances to be struck in communicating the best advice: between the rights of mother and child (and of women more generally), between clarity of message and risk of undue anxiety, and between simplicity of advice and the credibility of that advice – and, by extension, the likelihood it will be followed.

The Chief Medical Officers’ consultation on the communication of the guidelines, and the wording of the guidance itself, reflected an awareness of these complicated balancing acts, but this study suggests that more needs to be done.

For example, the authors suggest that we need to be clearer about the rationale for suggesting that pregnant women shouldn’t drink at all. Is it because the evidence we have is not considered reliable, or because of the absence of evidence proving that low levels of drinking cause no harm? Is it because the risks pregnant women run should be much lower than among the rest of the population? If so, who sets the bar? The authors recommend that guidance and communication of evidence be ‘layered’ to enable women to explore and share information to a depth that suits their own needs.

Practically these questions matter, because we need advice that is useful and meaningful. Ethically they matter because the science is complex – and so the balance between improving knowledge (which may tend towards more complex messages) and seeking to influence behaviour (which will tend towards simplicity) needs to be acknowledged.

These challenges are complex, and resolving them to everyone’s satisfaction even more so. But the goal is for babies and parents to be healthy, physically and mentally, so getting the balance right is vital.