Early maternal perceived stress and children's BMI: longitudinal impact and influencing factors

Maternal perceived stress has been discussed to contribute to the development of childhood overweight. Our aim was to investigate the longitudinal relationship of early maternal perceived stress and BMI z-scores in preschool children (≤ five years). A longitudinal analysis was conducted in 498 mother-child pairs of the German prospective birth cohort LINA with information on maternal perceived stress during pregnancy, one and two years after birth. BMI z-scores were based on annual measurements of children's weight/height and calculated based on WHO reference data. General estimation equations were applied to evaluate the impact of maternal stress on children's longitudinal BMI z-scores. Potential stressors contributing to the perceived stress of the mother were assessed by linear regression models. Using mediation analyses we evaluated the relationship between stressors, maternal perceived stress, and children's BMI z-score development. Postnatal maternal stress during the first year after birth had a positive longitudinal relationship with children's BMI z-scores up to the age of five years. Gender-stratified analyses revealed that only girls showed this positive association while boy's BMI z-scores were unaffected by maternal stress. We identified three neighborhood strains and two socio-demographic factors, which contributed to the maternal perceived stress level. Stressors themselves did not directly affect girl's BMI z-scores but rather mediated their effect through the perceived stress level. While different stressors contribute to maternal stress, the perceived stress level - rather than the stressors themselves - is strongly positively associated with BMI z-score development in girls.