PCoA based on an unweighted Unifrac dissimilarity matrix showing bacterial community composition of infant stool samples (7 days and 1, 2, 6 and 18 months), maternal stool samples (pre-delivery, 7 days, 6 and 18 months), and maternal vaginal/rectal swabs (pre-delivery and delivery) (A). Mean unweighted Unifrac distance of delivery maternal vaginal/rectal swabs or 6 months maternal stool to paired, vaginally born infant stool samples at each time point (B).