Association of Maternal Gestational Weight Gain With the Infant Fecal Microbiota.

OBJECTIVES: Pregnancy characteristics may influence the infant fecal microbiota during early life. We aimed to examine associations of maternal gestational weight gain with infant fecal microbiota composition, bacterial community richness, and Shannon diversity index.

METHODS: We analyzed data from a prospective cohort study of healthy infants. We collected prenatal data, including report of mother's gestational weight gain, and infant fecal samples from 84 infant-mother dyads. By applying 16S rRNA gene sequencing and an unbiased clustering by partitioning around medoids using Bray-Curtis distances, we identified 4 fecal microbiota profiles, and examined the associations of maternal gestational weight gain with the 4 fecal microbiota profiles, bacterial community richness, and Shannon diversity index.

RESULTS: Overall, the median age of infants was 4.0 months and 43% were girls. The mothers of the 84 infants gained a mean of 14.2 kg (standard deviation, 5.4 kg) during pregnancy. We identified 4 distinct microbiota profiles: Bifidobacterium-dominant (42%), Enterobacter/Veillonella-dominant (23%), Bacteroides-dominant (19%), and Escherichia-dominant (17%). Infants whose mothers had higher gestational weight gain were less likely to have a Bacteroides-dominant profile, corresponding to a relative risk ratio of 0.83 (95% confidence interval, 0.71-0.96; P = 0.01) per 1 kg increase in weight. In addition, higher gestational weight gain was also associated with lower bacterial community richness and Shannon diversity index (P < 0.05).

CONCLUSIONS: In this prospective cohort study of healthy infants, maternal gestational weight gain was associated with the infant fecal microbiota profiles, bacterial community richness, and Shannon diversity index.