Moderate alcohol consumption during pregnancy and the incidence of fetal malformations: a meta-analysis.

To determine whether there is an association between moderate alcohol consumption in the first trimester of pregnancy and increased risk of fetal malformations, we conducted a literature search using Medline (1966-present), PsycLit (1974-1995), and EMBASE (1988-1995). The following inclusion criteria were used to select the studies to be evaluated: 1) pregnant women; 2) moderate alcohol consumption (> 2 drinks/week to 2 drinks/day); 3) case-control or cohort studies; 4) presence of an abstainer group (0 to 2 drinks/wk); 5) outcome measures include major or minor malformations; 6) papers published in the English language. The exclusion criteria were: 1) studies in which moderate alcohol consumption could not be confirmed; 2) case reports, and editorials. The Methods section of each study was examined independently by two blinded investigators with a third investigator settling any disagreement. The number of malformations in the abstainer and moderate alcohol consuming groups in two by two tables. Out of 24 studies which met the inclusion criteria, only seven had extractable data. The included studies evaluated 130,810 pregnancy outcomes, with 24,007 in the moderate alcohol group and 106,803 in the control group. An overall Mantel-Haenszel odds ratio showed that the relative risk for fetal malformations was 1.01 with 95% confidence limits of 0.94 to 1.08 and a chi-square for homogeneity of 8.26 (p = 0.220). Quality of the studies did not correlate with their showing negative or positive association. Moderate alcohol consumption during the first trimester of pregnancy is not associated with increased risk of fetal malformations.