Associations Between Maternal Probiotic Intake, Gut Microbiota, and Temperament in 5–6-year-old Children

Abstract

Temperament, which reflects early-emerging patterns of emotional reactivity and regulation, is a key predictor of later emotional and psychological outcomes. While temperament is influenced by genetic and environmental factors, recent evidence highlights the potential importance of the gut–brain axis as an influencing factor. Maternal gut microbiota and probiotic intake during pregnancy may influence foetal neurodevelopment through multiple pathways, yet their potential role in shaping child temperament remains unclear. This study investigates the associations between (1) maternal probiotics and/or fish oil supplementation during pregnancy and child temperament, and (2) maternal gut microbiota composition and diversity during pregnancy and child temperament. In this study, data were derived from a randomised, double-blind, placebo-controlled trial including 439 pregnant women with overweight or obesity. Participants were randomized to receive probiotics, fish oil, probiotics and fish oil, or placebo until six months postpartum. Maternal faecal samples collected during pregnancy were analysed using metagenomic sequencing. Child temperament at 5–6 years (n=146) was assessed using the Very Short Form of the Children's Behavior Questionnaire. Statistical analyses in R were used to examine group differences in temperament outcomes between intervention groups, and regression models to assess associations between maternal microbiota characteristics, including composition and diversity, and child temperament. Combined supplementation of fish oil and probiotics was associated with a higher negative affect in children. No significant associations were observed between maternal gut microbial diversity and temperament outcomes. However, a lower abundance of a bacterium, Lawsonibacter sp. NSJ 51 was associated with higher surgency scores. Our results suggested that maternal probiotic intake and gut microbiota composition during pregnancy have limited associations with child temperament at ages 5–6 years. Nevertheless, the findings suggest a role of maternal nutrition and gut microbiota in shaping behavioural outcomes, while underscoring the complexity of these relationships, warranting further studies on the topic.