Many observational studies have been published on the topic of alcohol consumption in pregnant women and its effects on the development of fetus and child. The association of heavy maternal alcohol consumption during pregnancy and various adverse birth outcomes has been well established.1,2 Also, excessive alcohol consumption during pregnancy is associated with adverse postnatal behavioural development.3 However, studies focused on the associations of low to moderate alcohol consumption during pregnancy with birth outcomes showed inconsistent results.4–9 In general, low to moderate maternal alcohol consumption is considered as an average of one alcoholic drink at most per day. Some studies did not find any associations, whereas others found adverse or even beneficial effects. A recent systematic review by Henderson et al.10 also reported no convincing evidence for adverse effects of low to moderate maternal alcohol consumption on pregnancy outcomes, such as miscarriage, stillbirth, fetal growth restriction, prematurity, low birthweight, small for gestational age (SGA) at birth and birth defects including fetal alcohol syndrome. The authors were not able to perform a meta-analysis because of the high heterogeneity in the methods of the various studies used in their systematic review. They suggested that differences in results between studies might be the result of differences in study design and in timing and methods of assessment of maternal alcohol consumption. Also, differences in adjustment for possible confounding factors between the studies may explain inconsistent results. The aim of this systematic review and meta-analysis was to assess the dose–response association of maternal alcohol exposure before and during pregnancy with the risks of low birthweight, preterm birth and SGA.