Yet, there's "some evidence that even light alcohol consumption in pregnancy is associated with risk of delivering a small baby and, to some extent, also with the risk of premature delivery, although this was less clear", said review lead author Loubaba Mamluk.
There's been little research into low to moderate alcohol use during pregnancy, specifically drinking up to one or two drinks a week.
According to The Independent, official NHS guidance published only past year said "expectant mothers should not drink at all because 'experts are still unsure exactly how much - if any - alcohol is completely safe for you to have while you're pregnant'".
Last year Dame Sally Davies, the chief medical officer, issued fresh guidance on alcohol, saying: "Although the risk of harm to the baby is low if [mothers] have drunk small amounts of alcohol before becoming aware of the pregnancy, there is no "safe" level of alcohol to drink when you are pregnant".
A research team from Bristol University, UK, says light alcohol consumption during pregnancy may lead to premature delivery.
Of course, this does not mean that light drinking is totally safe, the researchers point out.
"There is a continual attempt, especially in Europe, to show that it is okay to drink quote unquote amounts of alcohol during pregnancy", said Grunebaum. However, women should still avoid alcohol during pregnancy, just to make sure they don't experience any unpleasant events.
Dr Christoph Lees, clinical reader in obstetrics at Imperial College London, said: "Whilst it is possible that light drinking is associated with a slightly higher risk of having a small baby, there are other possible explanations".
"Evidence of the effects of drinking up to 32 g/week in pregnancy is sparse". The question is light drinking is good or not.
As for other research that suggests low amounts of alcohol have zero effect on pregnancy, Grunebaum says these assertions may be an attempt to make drinking certain amounts socially acceptable in some countries.
Despite research, experts are still unsure how much alcohol - if any - is safe to drink while pregnant.
During the nine months of pregnancy, many pregnant women have wondered - would one or two glasses of wine really put my baby at risk?
"Formulating guidance on the basis of the current evidence is challenging".
Pregnant women who drink up to two standard glasses of wine a week are unlikely to harm their unborn baby, a new study suggested.
Andrew Shennan, professor of obstetrics at King's College London, said: "It has been hard to associate low levels of alcohol intake in pregnancy and harm, and this work confirms this". It also shows the failure of researchers so far to focus on light versus no alcohol consumption instead of moderate and heavy alcohol consumption.