A research team from Bristol University, UK, says light alcohol consumption during pregnancy may lead to premature delivery.
Before now, it was believed that it is safe for women to consume little quantities of alcohol without causing the baby any harm.
The research team, which reviewed all the available studies done on the topic since the 1950s, found no convincing proof that a drink or two a week is harmful.
However, they warn that this does not make alcohol completely safe for pregnant women.
They say women should avoid all alcohol throughout pregnancy “just in case” in accordance with official guidelines.
It had earlier been established that getting drunk or binge drinking during pregnancy can increase the risk of miscarriage, premature birth and lead to mental or physical problems in the baby called foetal alcohol syndrome.
Although the risks associated with light drinking are not defined, Luisa Zuccolo, a doctor at the university, and her colleagues found 26 relevant studies on the topic.
In seven of those studies, light drinking was associated with at least eight percent increased risk of having a small baby or a premature birth.
The review was published in BMJ Open.
“My advice to women is that it’s best not to drink at all if you’re trying for a baby or are pregnant,” said Russell Viner, a professor at the Royal College of Paediatrics and Child Health.
“Regularly drinking even small amounts could be harmful and should be avoided, in line with the precautionary approach.”
Follow us on twitter @Thecablestyle