A summary of single-locus association tests between ADH genotypes and three dimensions of alcohol drinking before and during pregnancy is presented in Figure 1, where inverse-logged P-values are plotted against each SNP's chromosomal position. The ‘peak’ corresponds to a SNP in ADH1B, rs1229984, for which there is evidence of association with average alcohol intake before (P-value = 0.001) and binge drinking during pregnancy (P-value = 9 × 10−4) (Fig. 1 and Table 2). There is also some evidence of association between rs2866151 (ADH1A) and weekly drinking before pregnancy (P-value = 0.006) (Fig. 1 and Table 2). In general, the associations are stronger when considering drinking before the index pregnancy, and attenuate for drinking during the period following recognition of pregnancy, in particular average weekly drinking in the first trimester (Table 2).
