Pregnant women who binge drink put their babies at significantly increased risk of being born underweight, landmark research by experts in Yorkshire finds for the first time.
Doctors say the results of a ground-breaking study in Bradford indicate that as many one in 10 babies born in the city have a lower-than-expected birthweight because their mothers continue to drink more than the recommended daily alcohol limits.
They found women drinking at least five units of alcohol a day – equivalent to around half a bottle of wine or two pints of medium-strength beer – between three and six months into their pregnancy had a 68 per cent increased risk of having a small baby.
They uncovered no link between binge drinking and premature birth and no increased risk of “small for dates” – babies being smaller than normal at a particular stage in pregnancy – among women drinking low or moderate amounts of alcohol during pregnancy.
The findings – the latest from the world-leading Born in Bradford project which is following thousands of babies delivered in the city – are the first to demonstrate a clear link between binge drinking and small babies.
Researchers also looked at the risks to babies from women who smoked during pregnancy, discovering that seven in 10 continued their habit while they were pregnant, leading to a doubling in the risk of having a premature or small baby.
Lead author Duncan Cooper said the findings provided clear evidence of a link between alcohol consumption and the risk of foetal growth restriction. “Growth-restricted babies have a greater risk of various neonatal complications including breathing problems, respiratory infections and hypothermia and impaired neurodevelopment,” he said.
“Our findings support government policy that while there is no risk from drinking small amounts of alcohol during pregnancy, women should not binge drink as there are significant risks and consequences for their unborn child.”
Official recommendations say pregnant women should avoid alcohol in their first three months of pregnancy, but if they choose to drink they should not consume more than one to two units once or twice a week.
They warn binge drinking should be avoided altogether as heavy and regular alcohol intake can cause foetal alcohol spectrum disorder, which may lead to premature births, low-birthweight babies and permanent health problems in children.
The researchers studied the alcohol habits of nearly 11,000 mothers between 2007 and 2010. Alcohol consumption and smoking was rare among Asian mothers but among white mothers of British origin 15 per cent smoked and more than 40 per cent drank alcohol.
A quarter of women binge drank before falling pregnant, nine per cent continued to do so in the first three months and more than 300 (three per cent) did so while three to six months pregnant.
Recent European studies estimate that between 30 and 70 per cent of women consume alcohol during pregnancy, while the numbers binge drinking can vary from three per cent to 26 per cent.
Prof John Wright, head of the Born in Bradford study, said: “Alcohol consumption during pregnancy is a contentious topic but this research demonstrates a clear link between binge drinking during pregnancy and having a small baby. The message that women should abstain completely from drinking during pregnancy is the safest policy and one that is adopted by most countries.”
Shirley Brierley, consultant in public health for Bradford Council, said women should also avoid alcohol while pregnant or trying to conceive. “If you drink a high volume during pregnancy, your baby is at risk of developing brain abnormalities and other health problems.”