Published: 20 January 2020
A comprehensive review of studies has found that drinking alcohol during #pregnancy can affect the child’s cognitive abilities later in life.
The researchers, from the NIHR Applied Research Collaboration West (ARC West), recommend that ‘Drymester’ - abstaining completely from alcohol while pregnant in all trimesters - is the only safe approach.
To study the effects of drinking alcohol during pregnancy, the researchers for the first time combined results from 23 previously published studies.
The researchers included traditional studies, such as randomised controlled trials, alongside alternative designs, such as comparing children in the same families whose mothers cut down or increased their alcohol use between pregnancies. Because the review incorporated studies with very different designs, the review results are less likely to contain errors or biases.
The review of these combined studies showed moderately strong evidence that prenatal alcohol exposure has a negative effect on cognitive outcomes of children. The review, published in the International Journal of Epidemiology, also found evidence that it could lead to lower birth weight.
The researchers concluded that women should continue to be advised to abstain from alcohol during pregnancy.
Research on how drinking during pregnancy affects children has traditionally been carried out in ‘observational’ studies, where participants are already exposed to a risk factor and researchers do not try to change who is or isn’t exposed.
With this type of study, it can be impossible to unpick which outcomes caused by alcohol, and which are caused by other factors. These factors could include a woman’s education or family environment, as well as genetic predisposition, which can affect her child’s development and cognition in the long-term.
Alternative study designs use different ways of minimising or removing these ‘confounding’ factors. If the results of these studies all point in the same direction, then the results are more reliable. All the studies included in the review tried to compare like with like groups of people who were only different in terms of exposure to alcohol during pregnancy.
The review was not geared up to establish the amount of alcohol that leads to these negative outcomes. However, the researchers concluded that women should continue to be advised to abstain from alcohol during pregnancy, as recommended by the UK Chief Medical Officer’s guidance.
Luisa Zuccolo, the study lead and Senior Lecturer at the University of Bristol, said:
“The body of evidence for the harm that alcohol can do to children before they’re born is growing, and our review is the first to look at the full range of studies on the issue. This is unlikely to be a fluke result, as we took into account a variety of approaches and results.
“Our work confirms the current scientific consensus: that consuming alcohol during pregnancy can affect one’s child’s cognitive abilities later in life, including their education. It might also lead to lower birth weight.”