Maternal exposures and the infant gut microbiome: a systematic review with meta-analysis

Abstract

Early life, including the establishment of the intestinal microbiome, represents a critical window of growth and development. Postnatal factors affecting the microbiome, including mode of delivery, feeding type, and antibiotic exposure have been widely investigated, but questions remain regarding the influence of exposures in utero on infant gut microbiome assembly. This systematic review aimed to synthesize evidence on exposures before birth, which affect the early intestinal microbiome. Five databases were searched in August 2019 for studies exploring pre-pregnancy or pregnancy 'exposure' data in relation to the infant microbiome. Of 1,441 publications identified, 76 were included. Factors reported influencing microbiome composition and diversity included maternal antibiotic and probiotic uses, dietary intake, pre-pregnancy body mass index (BMI), gestational weight gain (GWG), diabetes, mood, and others. Eleven studies contributed to three meta-analyses quantifying associations between maternal intrapartum antibiotic exposure (IAP), BMI and GWG, and infant microbiome alpha diversity (Shannon Index). IAP, maternal overweight/ obesity and excessive GWG were all associated with reduced diversity. Most studies were observational, few included early recruitment or longitudinal follow-up, and the timing, frequency, and methodologies related to stool sampling and analysis were variable. Standardization and collaboration are imperative to enhance understanding in this complex and rapidly evolving area.

Impact of Maternal Intrapartum Antibiotics, and Caesarean Section with and without Labour on Bifidobacterium and Other Infant Gut Microbiota

“…In a general population birth cohort of 1654 infants, maternal IAP exposure was associated with reduced absolute quantities of bifidobacteria among vaginally delivered infants (6.80 vs. 7.14 log 10 (gene-copies/g faeces), p < 0.05), as well as their lowered abundance relative to other gut microbiota. These results are consistent with a systematic review of eight studies showing depletion of bifidobacteria in the gut microbiota of infants exposed to intrapartum antibiotics, although this difference did not persist to one month after birth in three studies [41]. They were also independent of maternal pre-pregnancy BMI, a determinant of bifidobacterial abundance in breast milk [42].…”

To Probiotic or Not to Probiotic: A Metagenomic Comparison of the Discharge Gut Microbiome of Infants Supplemented With Probiotics in NICU and Those Who Are Not

“…To assess the difference between the probiotic and non-supplemented preterm infants across the entire cohort, while accounting for known associates to the infant gut microbiome, we assessed alpha diversity, beta diversity and taxonomic abundance using mixed effects models. The covariates included; maternal antibiotics ( 47 ), maternal diabetes ( 48 , 49 ), chorioamnionitis ( 50 ), preeclampsia ( 51 ), maternal diabetes ( 48 ), mode of delivery ( 50 , 52 ), infant diet ( 53 , 54 ), gestational age, NEC ( 55 , 56 ), infant sepsis ( 57 , 58 ), neonatal antibiotics ( 59 ) and ROP ( 60 ). For beta diversity, we performed an EnvFit analysis from the Vegan package ( 61 ), which compares the differences in the centroids relative to total variation.…”

Therapeutic Advances in Gut Microbiome Modulation in Patients with Inflammatory Bowel Disease from Pediatrics to Adulthood

“…Although the gut microbiome after three years of age is considered more "adultlike" [29], with a stable "signature" already established [30][31][32], there is ongoing adaptation to this ecosystem. Ringel-Kulka et al investigated the differences in the microbiomes between healthy children and adults using high throughput microarray analysis.…”