Effects of maternal probiotic supplementation on breast milk microbiome and infant gut microbiome and health: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: The early life microbiome is formed during the perinatal period and is critical for infants' lifelong health. This is established by maternal-infant microbiome crosstalk, which is mediated by the breast milk microbiome. The milk microbiome is dependent on the maternal gut microbiome, suggesting that it could potentially be restored through oral probiotic supplements. Therefore, we conducted this systematic review and meta-analysis to summarize the effect of maternal probiotic supplements on breast milk and infant gut microbiome, and infant health.

DATA SOURCES: PubMed, EMBASE, Web of Science, Scopus, CINAHL, and Science Direct databases were searched until December 15, 2022.

STUDY ELIGIBILITY CRITERIA: Randomized controlled trials with the PICO (population: pregnant or lactating women, intervention: probiotics, control: placebo or follow-up, outcome: breast milk and infant gut microbiome, and infant health) principles were included.

METHODS: The standard mean difference (SMD), risk difference (RD), and risk ratio (RR) with a 95% confidence interval (CI) using a random effect model were used to measure each outcome. All analyses were conducted with the intention-to-treat approach. Heterogeneity was evaluated using I2 statistics.

RESULTS: The final dataset included 24 RCTs with a total of 2761 mothers and 1756 infants. The overall effect of probiotics on the beneficial bacteria detection rate (RD) in breast milk was 24% (95% CI:0.11, 0.37, P=0.00, I2 = 91.12%). The pooled mean beneficial and pathogenic bacteria abundance in breast milk was SMD:1.22 log10 CFU/ml (95% CI:0.48, 1.97, P=0.00, I2= 95.51%) and -1.05 log10 CFU/ml (95% CI: -1.99, -0.12, P=0.03, I2= 96.79%)) respectively. The overall abundance of beneficial bacteria in the infant gut was SMD:0.89 log10CFU/g (95% CI:0.22, 1.56, P=0.01, I2 = 95.01%). It also controlled infant weight gain (SMD: -0.49 Kg/equivalent age, 95% CI: -0.82-, -0.17, P=0.00, I2 =0.00%), and decreased the occurrence of infantile colic (RR:0.30, 95% CI:0.16, 0.57, P=0.00, I2 =0.00%).

CONCLUSION: Maternal probiotic supplements effectively orchestrate the breast milk and infant gut microbiome, with a wide range of clinical benefits and safety. Lactobacillus, Bifidobacterium, S. thermophilus, and S. boulardii can be used as maternal supplements to promote infant health.