The purpose of this study is to determine whether antibiotics given immediately after birth
alter the development of the developing preterm infant's microbiome, which may further alter
overall clinical outcomes.
Inclusion Criteria for antibiotic randomization:
1. Infant must be born between the gestational ages of 28 0/7 weeks and 34 6/7 weeks
2. Infant must be born at investigator's home institution.
3. Infant must be considered to have a low risk of infection by one of the following
1. Delivered for maternal indications (Cesarean section or induction of labor for
maternal health, including pre-eclampsia, placental abruption, history of
intrauterine fetal demise (IUFD)/abruption, multiple gestation requiring preterm
delivery, etc) -OR-
2. Delivered due to preterm labor to a mother without the diagnosis of
chorioamnionitis/maternal fever or prolonged rupture of membranes >18 hours
Exclusion Criteria for antibiotic randomization:
1. Signs of clinical illness within the first 3 hours of life:
1. 5-minute Apgar <5
2. Requiring vasoactive drugs
4. Significant respiratory distress requiring supplemental oxygen >40%
2. Immature:Total (I:T) Ratio of >0.2 on initial complete blood count (CBC)
3. Congenital anomalies, including renal anomalies requiring serum antibiotic level
ANY infant born between the gestational ages of 28 0/7 weeks and 34 6/7 weeks who do not
meet inclusion criteria, with parental consent, can participate in the stool analysis only
arm of the study.