Background

Alcohol is associated with several adverse health conditions including liver disease, heart disease, stroke and cancer.¹ Alcohol-related harm is a major public health issue in the UK and across the world. In 2016, alcohol was estimated to the seventh leading risk factor of all deaths across the world, accounting for approximately 5.2% of all deaths.² This translates to more than 3 million deaths each year. In the UK, the Chief Medical Officers recommend that members of the general population consume no than 14 units of alcohol a week regularly, and if you do drink 14 units a week, it is best to spread this consumption evenly over three days or more.

Drinking alcohol in pregnancy

Recent research has estimated alcohol use in pregnancy to be just under 10%.³ During pregnancy, alcohol reaches the growing baby through the placenta. The baby’s liver is unable to process alcohol the way an adult is able to and exposure to alcohol can affect their development in several ways. In the first trimester (three months), alcohol consumption increases the risk of miscarriage, premature birth and the baby being born with a low birth weight. Alcohol consumption later in the pregnancy can lead to other health effects in childhood such as behavioural difficulties, impaired intellectual ability and mental health conditions.⁴

Foetal alcohol syndrome

Heavy consumption of alcohol during pregnancy can result in a specific syndrome called foetal alcohol syndrome. This condition results in babies suffering from poor growth in infancy and childhood, facial abnormalities as well as learning difficulties.⁴ A recent study estimated that one in every 67 women who consumed alcohol during pregnancy would deliver a child with foetal alcohol syndrome.³

Is there a safe level of alcohol consumption in pregnancy?

Recent research which received much media interest analysed all published research on the effects of low-to-moderate levels of alcohol consumption in pregnancy on pregnancy itself and longer-tern outcomes upon the child.⁵ This was the most comprehensive systematic review to date on this issue and found that there are ‘surprisingly’ few research studies prospectively researching the issue of whether light maternal alcohol consumption (defined as up to 4 units per week during pregnancy) has a causal effect upon the infant’s health, additional future offspring outcomes or pregnancy outcomes. Therefore, they concluded, there is a lack of evidence demonstrating a clear detrimental effect, or a safe limit of alcohol consumption. This finding does not mean that it is safe to drink up to 4 units a week, instead, this research highlights that the evidence is not sufficient to answer the question conclusively. In light of this, current national guidelines still emphasise that the safest level of alcohol consumption during pregnancy for both mother and baby is zero.

What do the experts say?

The Chief Medical Officers of the UK countries recently updated their guidance and advise that for women who are pregnant, or those planning a pregnancy, the safest approach to alcohol is to drink no alcohol at all. This approach minimises risks to the foetus. The Chief Medical Officers assert that drinking alcohol during pregnancy can lead to long-term harm to the unborn baby, and importantly the more alcohol that is consumed during pregnancy, the greater the risk.⁶

Alcohol consumption in prospective fathers

There has been uncertainty in the literature regarding potential effects of alcohol consumption in men upon semen quality. The most comprehensive review to date, including more than 16,000 men, found that alcohol intake has a detrimental effect upon semen volume.⁷ The findings suggest that moderate consumption of alcohol did not adversely affect semen parameters compared to daily or heavy consumption. However, the evidence remains inconclusive, and further research is required to aid clinical guidance.

Main points

• Alcohol is associated with many serious health conditions including heart disease, cancer, stroke and liver disease.
• The UK Chief Medical Officers recommend that even when not pregnant you should consume no than 14 units of alcohol a week.
• Alcohol reaches the unborn baby through the placenta.
• The unborn baby’s liver is unable to process alcohol and exposure increases the risk of miscarriage, premature birth, behavioural problems, mental health problems and the baby being born under-weight.
• One in every 67 women who drink during pregnancy give birth to a child with foetal alcohol syndrome. This can impair development and result in facial abnormalities, among other symptoms.
• There is insufficient evidence detailing the effects of minimal alcohol consumption during pregnancy. For this reason, national guidelines suggest that pregnant women should not drink at all.
• There is some evidence to suggest that men who drink alcohol may reduce their semen volume.

References

1. Forouzanfar MH, Alexander L, Anderson HR, Bachman VF, Biryukov S, Brauer M, et al. Global, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks in 188 countries, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet. 2015;386(10010):2287-323. doi: 10.1016/S0140-6736(15)00128-2.
2. Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. The Lancet. 2017;390(10100):1345-422. doi: https://doi.org/10.1016/S0140-6736(17)32366-8.
3. Popova S, Lange S, Probst C, Gmel G, Rehm J. Estimation of national, regional, and global prevalence of alcohol use during pregnancy and fetal alcohol syndrome: a systematic review and meta-analysis. The Lancet Global Health. 5(3):e290-e9. doi: 10.1016/S2214-109X(17)30021-9.
4. Chudley AE, Conry J, Cook JL, Loock C, Rosales T, LeBlanc N. Fetal alcohol spectrum disorder: Canadian guidelines for diagnosis. Canadian Medical Association Journal. 2005;172(5 suppl):S1-S21. doi: 10.1503/cmaj.1040302.
5. Mamluk L, Edwards HB, Savović J, Leach V, Jones T, Moore THM, et al. Low alcohol consumption and pregnancy and childhood outcomes: time to change guidelines indicating apparently ‘safe’ levels of alcohol during pregnancy? A systematic review and meta-analyses. BMJ Open. 2017;7(7). doi: 10.1136/bmjopen-2016-015410.
6. UK Chief Medical Officers. UK Chief Medical Officers’ Alcohol Guidelines Review https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/489795/summary.pdf2016.
7. Ricci E, Al Beitawi S, Cipriani S, Candiani M, Chiaffarino F, Viganò P, et al. Semen quality and alcohol intake: a systematic review and meta-analysis. Reproductive BioMedicine Online. 2017;34(1):38-47. doi: https://doi.org/10.1016/j.rbmo.2016.09.012.