An Investigation into the Impact of Maternal Dietary Intakes, Well-being and Breastfeeding on Longitudinal Child Health

Pregnancy is a unique time in that the health and behaviour of one individual can have a lasting impact on the offspring, from infancy through to adulthood. Therefore, understanding maternal health factors during pregnancy and how they underpin offspring health is critical. This thesis uses data from 3 studies carried out during pregnancy; the ROLO longitudinal birth cohort study, the PEAR Study, and the MicrobeMom trial, to explore maternal health factors and their impact on infant and child health using cohort analysis. Maternal well-being was overall found to be reduced in early pregnancy. Increased maternal dietary intakes during pregnancy of fibre, magnesium and B vitamins were noted to be associated with increased maternal well-being. This may be facilitated by the beneficial effect of fibre on the gut-brain axis. It was interesting to note that maternal well-being was not associated with breastfeeding practices. Despite low well-being during pregnancy, mothers are still breastfeeding. Considering the low rates of breastfeeding, specifically in Ireland, it is important that modifiable risk factors for breastfeeding are addressed. Fetal growth is a complex, dynamic process that requires appropriate modelling. This work used growth trajectories of offspring from 20 weeks’ gestation until 5 years of age, which appropriately modelled longitudinal offspring growth. Blood lipid profiles in early and late pregnancy, and adherence to national dietary allowances, were not found to be associated with offspring growth in our cohort which featured predominantly infants with an average birthweight of 4.1 Kg. Modelling fetal and infant growth appropriately is essential to further understand how the maternal environment can alter offspring growth and development. Microbial dysbiosis may play a role in the development of obesity. Infant gut microbiome diversity at 1 month of age was assessed using alpha and beta diversity, determined using metagenomic shotgun sequencing. This research did not find any association between probiotic supplementation during pregnancy or dietary intakes and offspring gut health. However, well-being in late pregnancy and breastfeeding practices at 1 month postpartum were found to be beneficial for improving infant microbial diversity. Breastfeeding initiation and breastfeeding duration were also found to be associated with healthy eating behaviours in children at 5 years of age, as were maternal eating behaviours. Encouraging healthy breastfeeding practices is paramount for improving health outcomes of offspring. This thesis provides novel insights into maternal health factors that shape the pregnant environment, and how these may influence offspring health and play a role in childhood obesity. Public health policy should prioritise maternal mental health and dietary intakes, as well as encouraging women to continue with prolonged breastfeeding. Unique opportunities for intervention during pregnancy are presented. The importance of longitudinal follow-up studies after pregnancy and the use of cohort analysis to define correlations that can inform future clinical trials is explored. Optimising the health of mothers is crucial to improve long-term health outcomes of future generations.