SRP410257 PRJNA906107 Characterizing microbiome dynamics among maternal and donor breastmilk and infants A total of 36 infants were included in the study, with 74 serial breastmilk samples collected approximately 2 weeks apart from each other. The mean infant gestational age was 29 weeks (range 23-39 weeks). The mean maternal age was 33 years ( range 21-42 years). 11/36 (31%) of infants were born by vaginal delivery. 22/36 (61%) of mothers received antibiotics during delivery. 11/36 (31%) of mothers received antibiotics prenatally.