There is little substantive evidence that binge drinking while pregnant seriously harms the developing fetus, finds a study in the Journal of Epidemiology and Community Health.
Consistently heavy drinking throughout pregnancy has been associated with birth defects and subsequent neurological problems. But it is not known what impact binge drinking, in the absence of regular heavy drinking, might have. And this drinking pattern is becoming increasingly common, particularly among women, say the authors.
Their findings are based on a comprehensive review of published research on binge drinking and women who were either pregnant or trying to conceive.
Binge drinking was taken to mean downing five or more alcoholic drinks in one go, equivalent to 60 g of alcohol or 7.5 units.
The period under review spanned 35 years from 1970 to 2005, and unearthed more than 3500 articles, which were narrowed down to 14 pieces of relevant research.
The researchers noted some methodological flaws in the 14 studies, although they were all assessed as being of good quality.
The results indicated that there was little substantive evidence that binge drinking caused a range of problems, including miscarriage, stillbirth, abnormal birthweight or birth defects, such as fetal alcohol syndrome.
But there was some suggestion that it might impair normal neurodevelopment, although the effects were generally quite small, say the authors.
These included "disinhibited behaviour," reduced verbal IQ, an increased tendency towards delinquent behaviour, learning problems and poorer academic performance.
They point out that the timing of binge drinking might be important, and that there may be more impact during the first 13 weeks of pregnancy, for example.
"This systematic review found no convincing evidence of adverse effects of prenatal binge drinking, except possibly on neurodevelopmental outcomes," they write.
They suggest that further research is required, but in the meantime it might be wise to advise women to avoid binge drinking during pregnancy, just in case.
But they add: "When pregnant women report isolated episodes of binge drinking in the absence of a consistently high daily alcohol intake, as is often the case, it is important to avoid inducing unnecessary anxiety, as, at present, the evidence of risk seems minimal."