Influences of maternal nutrition and the gut microbiome on pregnancy and infant outcomes: results and challenges from the BABY1000 pilot study

Abstract

Maternal health prior to and during pregnancy, alongside the early childhood environment, influence disease risk across the life course and in subsequent generations. Maternal diet is one factor important in shaping the trajectory of offspring health and the composition and diversity of the gut microbiome. However, gaps remain in our understanding of diet–environment–microbiome relationships in pregnancy and how to feasibly study them using birth cohorts. This thesis aimed to: (1) determine the nature and impact of maternal exposures during the perinatal period, particularly diet, on the maternal and infant gut microbiome; and (2) assess the feasibility and acceptability of ‘BABY1000’; a pilot prospective birth cohort study. Assessment of these aims included a systematic review and meta–analysis, and an examination of qualitative and quantitative data from the BABY1000 study (n=225). In BABY1000 participants, the diet quality of women was largely inconsistent with Australian dietary recommendations. Diet quality was not associated with the gut microbiome of mothers or infants. The individual was the strongest predictor of maternal gut microbial composition and diversity, and the microbiomes of six–week–old infants were largely influenced by birth mode and breastmilk intake. We found that it is both feasible and acceptable to collect comprehensive biological, questionnaire, and health data from early pregnancy to two years, but that additional resourcing is required to maintain retention and adapt to unforeseen circumstances. The COVID–19 pandemic and associated public health orders impacted the study, both regarding fidelity to research protocols and participants’ pregnancy, postpartum and parenting experiences. Thesis findings contribute to the areas of maternal health, family research, nutrition, microbiology and implementation science, and will inform future cohorts hoping to answer ongoing questions regarding the Developmental Origins of Health and Disease.