The UK Chief Medical Officers’ advice to women is:
'Women who are pregnant or trying to conceive should avoid alcohol altogether. However, if they do choose to drink, to minimise the risk to the baby, we recommend they should not drink more than 1-2 units once or twice a week and should not get drunk.'
The National Institute for Health and Clinical Excellence (NICE) advises healthcare professionals (GPS and nurses):
- Pregnant women and women planning to become pregnant should be advised to avoid drinking alcohol in the first three months of pregnancy, because there may be an increased risk of miscarriage.
- Women should be advised that if they choose to drink alcohol while they are pregnant, they should drink no more than 1-2 units of alcohol once or twice a week. There is uncertainty about how much alcohol is safe to drink in pregnancy, but at this low level there is no evidence of any harm to their unborn baby.
- Women should be advised not get to drunk or binge drink (drinking more than 7.5 UK units of alcohol on a single occasion) while they are pregnant because this can harm their unborn baby.
- If women want to avoid all possible alcohol-related risks, they should not drink alcohol during pregnancy because the evidence on this is limited.
What is a unit of alcohol?
One unit of alcohol is about half a pint of bitter or ordinary lager (ABV [alcohol by volume] 4.5%), or a single measure of spirits (25ml).
However, a 175ml glass of wine (13% ABV) is 2.3 units and a pint of strong beer (ABV 8%) is 4.5 units. The number of units in particular drinks are different, depending on the strength of the alcohol in them and the volume of the drink.
How does alcohol affect my unborn baby?
If you drink alcohol when you’re pregnant, the alcohol crosses the placenta into the bloodstream of the unborn baby and could interfere with how it grows and develops. In the absence of its own blood filtering system, the foetus is unprotected from any alcohol molecules that cross from the mother’s blood.
Alcohol can cause damage to an unborn baby at all stages of pregnancy. Drinking during pregnancy has been associated with:
- miscarriage (over 9,000 women are admitted to hospital every year for miscarriages caused by alcohol [NHS Information Centre Hospital Admission data])
- low birth weight
- heart defects
- learning and behavioural disorders
The most severe of the alcohol-related conditions (which is normally due to heavy drinking in pregnancy) is Fetal Alcohol Syndrome (FAS). It causes:
- facial deformities
- problems with physical and emotional development
- poor memory or a short attention span
A wider range of intellectual and physical disabilities than those seen in FAS and partial FAS-like syndromes occur in babies born to mothers who drank alcohol at some time in the pregnancy. These are commonly grouped together under the umbrella term Fetal Alcohol Spectrum Disorders (FASD).
While these effects attributed to alcohol are still more common in heavier drinkers, the problems also seem to happen at much lower drinking levels than seen for FAS.
It is not yet clear whether there is any small amount of drinking in pregnancy that might be completely safe from the risk of FASD. Therefore, pregnant women are advised to avoid all alcohol during pregnancy.
FASD and FAS-related disabilities carry on into adulthood, and because those effects due to drinking alcohol would have been completely prevented if the mother had not drunk during pregnancy, it is considered important to take a precautionary approach in advising on risk.
Read the answers to more questions about pregnancy.
Further information:
