A study investigated the effects of low-to-moderate levels of maternal alcohol consumption in pregnancy on pregnancy and longer-term offspring outcomes. 24 cohort and two quasi experimental studies were included a the meta analysis.
The study found a limited number of prospective studies specifically addressing the question of whether light maternal alcohol consumption (i.e., up to 32 g/week (or 4 UK units) has any causal effect (adverse or beneficial) on infant and later offspring outcomes and pregnancy outcomes, and, as a result the study identified a paucity of evidence demonstrating a clear detrimental effect, or safe limit, of light alcohol consumption on outcomes.
The researchers did find that the odds of small for gestational age and preterm birth were higher for babies whose mothers consumed up to 32 g/week versus none, but estimates for preterm birth were also compatible with no association: summary OR 1.08, 95% CI (1.02 - 1.14) (seven studies, all estimates were adjusted) OR 1.10, 95% CI (0.95 - 1.28) (nine studies, includes one unadjusted estimates), respectively. The upper limit that researchers chose to examine is that of the current version of the UK National Institute for Health and Care Excellence guidelines.
The authors conclude that evidence of the effects of drinking ≤32 g/week in pregnancy is sparse. As there was some evidence that even light prenatal alcohol consumption is associated with being small for gestational age and preterm delivery, guidance could advise abstention as a precautionary principle but should explain the paucity of evidence
Source: Low alcohol consumption and pregnancy and childhood outcomes: time to change guidelines indicating apparently ‘safe’ levels of alcohol during pregnancy? A systematic review and meta-analyses. L Mamluk, HB Edwards, J Savovi?, et al. BMJ Open Volume 7, Issue 7.