Human milk microbiota development during lactation and its relation to maternal geographic location and gestational hypertensive status

Abstract

Bacteria in human milk could directly seed the infant intestinal microbiota, while information about how milk microbiota develops during lactation and how geographic location, gestational hypertensive status, and maternal age influence this process is limited. Here, we collected human milk samples from mothers of term infants at the first day, 2 weeks, and 6 weeks postpartum from 117 longitudinally followed-up mothers (age: 28.7 ± 3.6 y) recruited from three cities in China. We found that milk microbial diversity and richness were the highest in colostrum but gradually decreased over lactation. Microbial composition changed across lactation and exhibited more discrete compositional patterns in 2-week and 6-week milk samples compared with colostrum samples. At phylum level, the abundance of Proteobacteria increased during lactation, while Firmicutes showed the opposite trend. At genus level, Staphylococcus, Streptococcus, Acinetobacter, Pseudomonas, and Lactobacillus were predominant in colostrum samples and showed distinct variations across lactation. Maternal geographic location was significantly associated with the milk microbiota development and the abundance of predominant genus. In addition, milk from mothers with gestational prehypertension had a different and less diverse microbial community at genus level in early lactation times, and contained less Lactobacillus in the 2-week milk samples than those from normotensive mothers. Findings of our study outlined the human milk microbial diversity and community development over lactation, and underscored the importance of maternal geographic locations and gestational hypertensive status on milk microbiota, which might have important implications in the establishment of the infant intestinal microbiota via breastfeeding.

Breastfeeding Practices Influence the Breast Milk Microbiota Depending on Pre-Gestational Maternal BMI and Weight Gain over Pregnancy

“…Breastfeeding, maternal diet, pre-gestational BMI, weight gain over pregnancy, maternal age, genetics, and geographical location have been reported to influence breast milk microbial composition [ 8 , 9 , 15 , 17 ]. We have previously reported the impact of maternal diet on breast milk microbiota [ 8 ] in the same population being the fiber, and that both plant and animal proteins are the most important contributors.…”

“…Results regarding the potential impact of maternal body mass index (BMI) and weight gain over pregnancy on breast milk microbiota are also still contradictory [ 13 , 14 , 15 , 16 ]. Similarly, while other studies found differences in milk microbiota according to lactation period [ 13 , 17 ] and feeding method [ 9 ], others reported a stable composition over time [ 18 ]. Therefore, it would be essential to provide evidence on the possible factors that shape the composition of breast milk microbiota.…”

Role of cesarean section in the development of neonatal gut microbiota: A systematic review

“…Although there are higher complications with advanced maternal age [ 65 ], it has been shown that variables of maternal prenatal factors including geographic location, gestational hypertensive status, and maternal age did not affect the diversity of gut microbial taxa composition [ 66 ].…”

Comparison of Two Approaches for the Metataxonomic Analysis of the Human Milk Microbiome

“…Indeed, a growing literature supporting the crucial roles exerted by the human milk microbiota in maternal and infant health, in conjunction with advances in high-throughput sequencing (HTS) technologies, have led to a rapidly growing interest in the study of this microbial community and its variation, mainly in relation to maternal and infant factors. In this regard evidence suggests the existence of a strong inter-individual variation in the composition of the human milk microbiota across different populations, in relation to variable delivery factors ( Cabrera-Rubio et al., 2016 ; Hoashi et al., 2016 ; Asbury et al., 2020 ), lactation stage ( Khodayar-Pardo et al., 2014 ), maternal conditions (either chronic pre-pregnancy situations or those developed during pregnancy) ( LeMay-Nedjelski et al., 2020 ; Volery et al., 2020 ; Wan et al., 2020 ), lifestyle habits ( Moossavi et al., 2019 ; Padilha et al., 2020 ), psycho-social and economic conditions ( Ojo-Okunola et al., 2019 ), and infant health outcomes ( Demmelmair et al., 2020 ) as summarized previously in Ruiz et al (2019) and Lackey et al (2019) . More recently, a combination of HTS and culturomic approaches has further supported the existence of a diversity of viable bacterial cells in healthy human milk wider than previously anticipated, and has offered novel opportunities to conduct mechanistic studies on the metabolic potential of this microbial community ( Schwab et al., 2019 ; Togo et al., 2019 ; Treven et al., 2019 ).…”