PhD (Doctor of Philosophy)
Date of Award
Committee Chair or Co-Chairs
W. Andrew Clark
Sean Fox, Tammy R. Ozment, Jonathan M. Peterson, Christopher Pritchett, Carol L. Wagner
Preterm birth is the number one cause of death in neonates, accounting for 35% of neonatal mortality. The preterm birth rate in the U.S. in 2021 was 10.5%, disproportionally affected by race and ethnicity. Obese women have an increased risk of preterm pregnancy, and if delivered before 37 weeks of gestation, the offspring have higher rates of complications that extend from the neonatal period into life-long metabolic and immune adverse outcomes. In the early months after delivery, preterm infants have higher rates of adverse health outcomes than term infants, including infections, extrauterine growth restrictions, respiratory, metabolic, and neurological complications, necrotizing enterocolitis (NEC), and bronchopulmonary dysplasia (BPD). Diet for the preterm infant is crucial for infection prevention, and maternal breast milk is most beneficial when given in the first few days after birth.
Expectant and breastfeeding mothers should consume appropriate food and supplements to optimize their nutrition. In addition to nutrients, bioactive components, vitamins, and minerals found in breast milk (BM), there is evidence that microbes (microbiome) are a significant factor in infant development, contributing to protection against pathogens and playing a role in the development of the immune and nervous systems. Maternal BM composition and microbiome are affected by many factors, including maternal body mass index (BMI), maternal health, antibiotics use, mode of delivery, maternal parity, gestational age, and time and duration of lactation. Maternal body composition, however, and not maternal nutritional status, is associated with breast milk nutritional composition. Altogether, these maternal factors may modify the premature infant gut microbiome.
We examined the role of maternal adiposity and how it impacts the composition of human breast milk, specifically hormones, nutrient composition, short and long chain fatty acids, and microbiome. We also examined the role of maternal adiposity and how it impacts the short-chain fatty acids and microbiome in infant fecal samples. We found that maternal adiposity affects breast milk hormones, potentially modulating infant metabolism. Additionally, we found that maternal adiposity does not alter the nutrient composition of breast milk; however, differences in both short and long chain fatty acids and maternal adiposity were detected. In our small cross-sectional cohort of preterm infants, we did not observe differences in short-chain fatty acids in the preterm infant stool samples compared to maternal adiposity. Concerning maternal adiposity and its impact on the microbiomes of breast milk and infants, we observed differences in phyla and genera between the maternal BMI groups on the outcome of breast milk and preterm infant microbiomes but no statistical significance in alpha and beta diversities between the groups. Thus, our results indicate that maternal adiposity impacts hormonal, microbial composition, and short-chain fatty acid profiles in breast milk, which tremendously influences infant growth and development.
Dissertation - embargo
Thomas, Kristy L., "Investigating the Role of Maternal Adiposity on Human Breast Milk and Preterm Infant Stool Short Chain Fatty Acid and Microbiome Profiles" (2023). Electronic Theses and Dissertations. Paper 4319. https://dc.etsu.edu/etd/4319
Copyright by the authors.
Available for download on Wednesday, January 15, 2025