Why shouldn’t you drink alcohol when you are pregnant?

Whilst it is common knowledge that pregnant women are advised not to drink alcohol, not everyone is fully aware of why this is so important. Right up to the 1970s it was perfectly acceptable for pregnant women to both drink and smoke, and even up to 2007 government advice was to stay within the boundaries of “not more than one or two units once or twice a week”. Since 2007 UK advice is clear; pregnant women OR even women trying to conceive should not drink any alcohol at all. But what exactly are the risks to your baby if you drink? How did they discover you should not drink alcohol during pregnancy? And what if you have already drunk alcohol before you realised you were pregnant?

The Vulnerable First Trimester

The first trimester of pregnancy, from the moment of conception to the end of the 12th week, is a period of very intricate and rapid development for the embryo. During this time, crucial foundations of vital organs and physiological systems are put in place, and during these early formations the foetus is extremely vulnerable to any interference from toxic substances or pathogens. However, during this precarious early phase, many women are not yet aware of their pregnancy, so may not have changed their lifestyle accordingly.

When did they discover you shouldn’t drink alcohol in pregnancy?

The links between the consumption of alcohol and complications in pregnancy were first established in the early 1960s. A landmark research study conducted by Dr. L.K. Hansen and published in the British Medical Journal in 1963 noted a significant correlation between maternal alcohol use during pregnancy and a higher risk of problems with fetal development.

This pioneering study led the way to further research which has reinforced this conclusion. A study published in 1997 by Dr C.L. Smith and colleagues stated that intake of alcohol in the first three months of pregnancy can lead to cognitive deficits and behavioural issues in children. In 2020 research led by Dr J Hayes concluded that alcohol in the first trimester increased the likelihood of genetic changes in the developing embryo which impact long term health.

How can alcohol affect an embryo?

Alcohol passes directly from your bloodstream into the baby’s blood stream via the placenta and the umbilical cord. Whilst the placenta filters out many harmful toxins and pathogens from affecting the fetus, it does not filter out alcohol. Furthermore, the primitive systems of a developing embryo cannot metabolize alcohol and break it down in the same way that an adult can. As a result, the alcohol can stay in the baby’s blood for longer than it is in the mother’s. Even in the very early weeks before the placenta is developed, alcohol can pass to the embryo through the yolk sac.

Aside from the above issues with general development and potential genetic issues, other studies have shown that drinking alcohol may lead to an increased risk of other cellular damage. The neural tube, which develops at an early stage into the brain and spine is particularly vulnerable to toxins including alcohol. Facial development can also be affected by alcohol. The placenta may also be affected, leading to issues with restricted growth of the fetus, as concluded in a 2019 study (A Johnson et al).

 Does alcohol increase risk of miscarriage?

 A number of research studies have investigated whether alcohol in early pregnancy increases the risk of miscarriage. A 2007 study published in the American Journal of Obstetrics and Gynecology stated that this risk was significantly elevated. A further fascinating research project in 2014 published in the journal “Substance Use and Misuse” showed that women who drank four or more drinks per week in early pregnancy were 2.65 times more likely to miscarry. Drinking spirits were particularly of concern. Interestingly, the same study also showed that caffeinated drinks increase the risk of miscarriage. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4183196/

 What is fetal alcohol syndrome?

 Fetal alcohol syndrome, also known as FAS is a serious condition which babies may be born with as a result of exposure to alcohol within the womb. This condition can result in facial abnormalities and neurological difficulties. Fetal alcohol syndrome cannot be cured, even once the child is born and no longer exposed to alcohol. It is a life long condition. Children are sometimes diagnosed at birth based on specific facial appearance and often low birth weight, although sometimes they are diagnosed later following developmental issues and concerning behaviour. The child may have learning disabilities and fail to research certain progressive milestones.

 What are the effects of alcohol on the mother?

 Drinking alcohol has both physical and psychological effects on all of us. These effects could include increased stress or anxiety, blood pressure changes, cardiac stress, sleep issues and general fitness levels. A pregnant woman is particularly at risk due to the extra pressure her body is already under as it changes in order to cultivate another entire human. Abstaining from alcohol during early pregnancy is a critical step in increasing the likelihood of a good outcome and ongoing health for both the developing baby and the mother. The evidence cannot be argued with; science has proved that alcohol is not recommended.

 What percentage of women drink alcohol when they are pregnant?

 Due to increasing global awareness of the risks involved, drinking during pregnancy has decreased in recent years. Despite this, in 2017 some research was published following a study of European women who had all answered an anonymous questionnaire. The results showed that nearly 16% of women had drunk during their pregnancy, and this statistic was considerably higher in women from the UK (28.5%). https://pubmed.ncbi.nlm.nih.gov/28111037/

 What if I have already drunk alcohol before realising I was pregnant?

 Whilst the recommendation is to cease alcohol before conception, in reality, a large number of pregnancies are unplanned and lifestyles are not changed at the recommended early stages. Be reassured that drinking alcohol does not definitely mean that you will have caused problems for your pregnancy. Risks may be slightly higher but any positive lifestyle change is helpful, whenever it comes. Speak to your midwife regarding your concerns; if your clinicians feel you are particularly at risk of problems you may be more closely monitored. Nearly half of all pregnancies in the UK and the USA are unplanned, so this issue is common.

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