Br J Nutr. 2022 Sep 14:1-27. doi: 10.1017/S0007114522002938. Online ahead of print.
The objectives of this study were (1) to systematically review the literature on the association between birth weight in children born in the first and second generation; (2) to quantify this association by performing a meta-analysis. A systematic review was carried in six databases (Pubmed, Science Direct, Web of Science, Embase, Scopus, CINAHL and LILACS), in January 2021, for studies that recorded the birth weight of parents and children. A meta-analysis using random effects to obtain a pooled effect of the difference in birth weight and the association of low birth weight (LBW) between generations was performed. Furthermore, univariable meta-regression was conducted to assess heterogeneity. Egger’s tests were used to possible publication biases. Of the 9878 identified studies, 70 were read in full and 20 were included in the meta-analysis (10 prospective cohorts and 10 retrospective cohorts), 14 studies for difference in means and 11 studies for the association of LBW between generations (23 estimates). Across all studies, there was no statistically significant mean difference (MD) birth weight between first and second-generation (MD 19.26, 95% CI -28.85, 67.36; p= 0.43). Overall, children of LBW parents were 69% more likely to have low birth weight (pooled effect size (ES) 1.69, 95% CI 1.46, 1.95); I 2 : 85,8%). No source of heterogeneity was identified among the studies and no publication bias. The average birth weight of parents does not influence the average birth weight of children, however the proportion of LBW among the parents seems to affect the offspring’s birth weight.