Figure 4.

Vertical transmission of milk microbiota varies with maternal parity

(A) Across all infants, the infant gut microbiome shares ∼10% more ASVs with milk than with the maternal gut at T1 (2-5 days old). Transmission rates do not differ at T2 (4 months old).

(B) Infants born to low parity females exhibit stronger ASV sharing with the milk microbiome at T1 (2–5 days old) compared to infants of high parity females.

(C) Comparison of the three high-frequency ASVs across microbial communities suggests that milk is the primary reservoir for B. fragilis to the infant gut.