We performed fixed effects inverse variance meta-analyses of the association between each SNP and birth weight, including up to 43 discovery and follow-up samples of European descent (maximum total n = 69,308). Individual study results for any SNP showing strong evidence of deviation from Hardy-Weinberg Equilibrium (P <1×10−4) were excluded. Meta-analyses were performed in parallel at two different study centres, using two software packages in parallel (METAL 2009-10-10 release30 and GWAMA ver.2.0.631. We used Cochran’s Q test and the derived inconsistency statistic, I2 34 to assess evidence of between-study heterogeneity of effect size. Results that crossed the widely accepted genome-wide significance threshold of P < 5×10−8 were considered to represent robust evidence of association.
