Table 1 Participant characteristics and sample availability
Intervention group (n = 47) | Control group (n = 48) | p | |
|---|---|---|---|
Gestational age in weeks | 31 (30–32) | 30 (29–32) | 0.02 |
Birthweight in grams | 1580 (1370–1790) | 1348 (1118–1590) | 0.003 |
Z-score | −0.09 (−0.62–0.49) | −0.26 (−0.83–0.10) | 0.04 |
Male sex, n (%) | 21 (45) | 24 (50) | 0.69 |
White race, n (%) | 24 (51) | 27 (56) | 0.81 |
Hispanic/Latino ethnicity, n (%) | 9 (19) | 9 (19) | 1.00 |
Vaginal delivery, n (%) | 22 (47) | 18 (37) | 0.41 |
Multiple gestation, n (%) | 17 (36) | 12 (25) | 0.27 |
Maternal antibiotics, n (%) | 26 (55) | 24 (50) | 0.68 |
No exposure to antenatal steroids, n (%) | 5 (10) | 4 (8) | 0.66 |
Excessive fat mass, n (%) | 24/46 (52) | 15/42 (36) | 0.14 |
Cumulative enteral intake volume up to postnatal day 14 (ml/kg) | 1743 (1626–1841) | 1618 (1477–1683) | 0.0004 |
Cumulative maternal to donor milk ratio up to postnatal day 14 (%) | 55 (5−77) | 35 (3−88) | 0.56 |
Exposure to postnatal antibiotics within the first 48 h after birth, n (%) | 40 (85) | 41 (85) | 0.97 |
Exposure to antibiotics between postnatal days 3 and 14 | 11 (23) | 2 (4) | 0.006 |
Enteral supplementation with probiotics within the first week after birth, n (%) | 17 (36) | 33 (69) | 0.002 |
Postnatal age at the time of stool sample collection in days | 13 (12−13) | 13 (12−14) | 0.32 |
Postmenstrual age at the time of stool sample collection in weeks | 33 (32−34) | 33 (32−34) | 0.07 |
Library size | 35,920 (26,526−42,727) | 31,094 (23,627−39,046) | 0.23 |
