Objective The aim of this study was to review systematically the available evidence on studies in humans on the effects of low–moderate levels of prenatal alcohol consumption (up to 10.4 UK units or 83 g/week) compared with consumption of no alcohol on pregnancy outcome.
Design Systematic review.
Population Pregnant women or women who are trying to become pregnant.
Methods The search strategy included Medline, Embase, Cinahl and PsychInfo for the years 1970–2005. Titles and abstracts were read by two researchers and inclusion/exclusion being decided according to prespecified criteria. All the included articles were then obtained and read in full by the two researchers to decide on inclusion. The articles were assessed for quality using the Newcastle–Ottawa Quality Assessment Scales.
Main outcome measures Outcomes considered were miscarriage, stillbirth, intrauterine growth restriction, prematurity, birthweight, small for gestational age at birth and birth defects including fetal alcohol syndrome.
Results The search resulted in 3630 titles and abstracts, which were narrowed down to 46 relevant articles. At low–moderate levels of consumption, there were no consistently significant effects of alcohol on any of the outcomes considered. Many of the reported studies had methodological weaknesses.
Conclusions This systematic review found no convincing evidence of adverse effects of prenatal alcohol exposure at low–moderate levels of exposure. However, weaknesses in the evidence preclude the conclusion that drinking at these levels during pregnancy is safe.