When considering whether or not to have a kid, most Australian women probably have resigned themselves to the fact they will have to buy maternity clothing, ‘eat for two’ and change their lifestyle a little. But given that 70% of the population drinks monthly, many of them may not realise what the science says about drinking whilst pregnant and what the risks actually are.

9-Week Human Embryo from Ectopic Pregnancy by Ed Uthman

Early Pregnancy & Foetal Development

Up until day 21 of pregnancy, the mother’s blood surrounds the embryo allowing nutrient and waste to pass between them. Once the embryo develops into a foetus the link to the mother is established through the umbilical cord and placenta.

A blood barrier exists between the foetus and mother (which is why you don’t necessarily have the same blood type as your mother), nutrients are transferred to the foetus (eg oxygen, calcium etc) and waste goes back for the mother to process.

Alcohol in the B Stream

In every human, nutrients are broken down into simpler compounds by the digestive system and transferred throughout the body via the blood stream. When people drink alcohol (or ethanol, for the chemists out there) it travels through the stomach, where about a fifth is absorbed by the blood stream. The rest is absorbed by the small intestine.

Because ethanol is a small molecule which likes hanging out with water, it easily dissolves in the cells of the body. Once the body recognises that it has alcohol in its system, it begins to convert the alcohol to simpler molecules, water and carbon dioxide, and uses the energy released as part of this process.
For more info on this process have a look at How Stuff Works.

Effect of Heavy Drinking on Kids

There is a reasonable amount of scientific evidence demonstrating that the effect of heavy drinking on foetuses may result in foetal alcohol syndrome (FAS).

This level of alcohol consumption can have a teratogenic effect on children, interfering with their normal emotional development and potentially causing facial dismorphology, growth deficiencies and damage to the central nervous system.

Other substances which have this effect are cannabis and nicotine (one reason why smoking while you’re pregnant is also not encouraged!).

What about the occasional champagne?

However, many women still wonder if the occasional drink will harm their unborn child, especially given the recent release of at least two studies showing little to no effect on child development if the mother drinks “lightly”.

A 2012 Danish study compared drinking rates amongst pregnant women, researching the effect on the development of their children. Most media outlets reported the results as suggesting there was no difference in the development of children and the rate at which their mothers’ drank (including heavy drinking). However, when reading the journal article it was clear that the ‘no difference’ was rather a ‘we don’t have enough information to make any significant findings’ statement.

In a 2010 English study, things were more interesting. The researchers used a large sample size of over 11 000 children, following them until they were 5 years old. However, it was a self reporting study, which means it was up to the mothers to put down how much they drank. This type of study usually means the figures reported are less than the real drinking figure.

Nevertheless, the researchers found that if mothers were ‘light’ drinkers, their children were 30% less likely to have behavioural issues than teetotallers. However, behavioural and emotional issues did start to present at higher than normal rates for ‘moderate’ and ‘heavy’ drinkers.

Despite these results and everything else I have read, including the academic journals, it is suggested that these studies should not be used as a free pass. Certainly the evidence tends to suggest the risk of children developing behavioural issues as a result of their mothers light drinking is lower, but the recommendation from government agencies is still to avoid alcohol.