Table 1:
Infant demographic, delivery, and clinical characteristics
| Variable | Median [IQV] or n (%) | ||
|---|---|---|---|
| Overall cohort (n=88,574) | Antibiotic exposure days 0–2 (n= 75,353)1 | No antibiotic exposure days 0–2 (n= 13,221)1 | |
| Demographics | |||
| Gestational Age (weeks) | 28 [26 – 29] | 27 [26 – 29] | 29 [28 – 30] |
| Birth weight (g) | 1,004 [775 – 1,225] | 990 [760 – 1,220] | 1,070 [870 – 1,260] |
| Small for gestational age | 12,837 (15%) | 9,891 (13%) | 2,946 (22%) |
| Male sex | 45,408 (51%) | 39,283 (52%) | 6,125 (46%) |
| Race/Ethnicity2 | |||
| White, non-Hispanic | 38,192 (45%) | 31,889 (44%) | 6,303 (50%) |
| Black, non-Hispanic | 25,771 (30%) | 22,080 (30%) | 3,691 (29%) |
| Hispanic | 16,228 (19%) | 14,376 (20%) | 1,852 (15%) |
| Other3 | 5,074 (6%) | 4,200 (6%) | 874 (7%) |
| Perinatal characteristics | |||
| Multiple gestation | 22,838 (26%) | 19,655 (26%) | 3,183 (24%) |
| Delivery by Cesarean section | 65,163 (74%) | 53,201 (71%) | 11,962 (90%) |
| Antenatal corticosteroids | 75,879 (86%) | 63,796 (85%) | 12,083 (91%) |
| Prolonged ROM >18 hours | 15,301 (17%) | 14,927 (20%) | 374 (3%) |
| Chorioamnionitis | 298 (<1%) | 298 (<1%) | 0 (0%) |
| Maternal GBS status | |||
| Positive | 7,547 (9%) | 6,686 (9%) | 861 (7%) |
| Negative | 16,082 (18%) | 13,781 (18%) | 2,301 (17%) |
| Unknown | 64,945 (73%) | 54,886 (73%) | 10,059 (76%) |
| Initial management, DOL 0–2 | |||
| Mechanical ventilation | 56,900 (64%) | 51,794 (69%) | 5,106 (39%) |
| Surfactant administration | 61,521 (69%) | 54,387 (72%) | 7,134 (54%) |
| Vasopressor administration4 | 14,894 (17%) | 14,415 (19%) | 479 (4%) |
| Systemic corticosteroid exposure5 | 3,712 (4%) | 3,576 (5%) | 136 (1%) |
1.
All listed characteristics differ significantly among antibiotic-exposed versus unexposed infants (p≤0.001) by Pearson’s chi-square or Wilcoxon’s rank sum test
2.
Due to missing data, total number of infants with available race/ethnicity data equals 85,256 (72,545 antibiotic-exposed infants during days 0–2 and 12,720 antibiotic unexposed infants)
3.
Includes American/Alaska Native, Asian, Pacific Islander, and other
4.
Includes infusions of dopamine, dobutamine, epinephrine, norepinephrine, and/or milrinone
5.
Includes hydrocortisone or dexamethasone