The impact of maternal stress on offspring birth weight and the mediating effect of dietary patterns: the Shanghai Maternal-Child Pairs Cohort study

Background: Maternal stress and nutrition during pregnancy are two of the most commonly studied factors in the context of fetal development. However, few investigators have considered the combined effects of stress and diet in pregnant women and their offspring. Aims: To determine the impact of maternal stress on offspring birth weight, and the potential mediating role of maternal dietary patterns. Methods: A total of 3542 pregnant women and their singleton live births were recruited from Shanghai Maternal Child Pairs Cohort (Shanghai MCPC). Maternal stress was assessed using the Life Event Scale for Pregnant Women (LESPW) in early and late pregnancy. Food frequency questionnaire (FFQ) was performed to evaluate maternal diet in late pregnancy. Multiple linear regression was conducted to estimate the associations between maternal stress and child birth weight. Logistic regression was performed to calculate the association between maternal stress and small for gestational age (SGA)/large for gestational age (LGA). The bootstrap method was used to investigate the mediating effects of maternal dietary patterns. Results: Maternal subjective events stress (beta = 0.367) and total stress (beta = 0.079) in early pregnancy, and positive objective life events stress (beta = 0.275) in late pregnancy, were positively associated with birth weight. Maternal dietary pattern of "high-fat and sugar" mediated the associations between subjective events stress and total stress during early pregnancy and birth weight. An increased risk for LGA was observed among women exposed to relatively higher stress during early pregnancy (OR, 1.416; 95% CI, 1.035-1.937). No statistically significant associations were found between maternal stress during late pregnancy and child birth weight or SGA/LGA. Conclusions: Maternal life events stress during early pregnancy significantly increases neonatal birth weight and risk for LGA, which may mediate by a "high-fat and sugar" dietary pattern. Limitations: The lack of biological markers limits the explanation of the mechanism. The assessment of diet used food intake frequency to evaluate dietary characteristics, which may miss information of energy intake.