Baseline characteristics of the study participants for the total cohort and stratified by Ureaplasma status
| No. of participants (%) | ||||||
| Total cohort | Ureaplasma positive | Ureaplasma negative | ||||
| (n=121) | (n=44) | (n=77) | ||||
| Characteristic | AZM | Placebo | AZM | Placebo | AZM | Placebo |
| (n=60) | (n=61) | (n=19) | (n=25) | (n=41) | (n=36) | |
| Male, n (%) | 26 (43) | 32 (52) | 11 (58) | 10 (40) | 15 (37) | 22 (61) |
| Race, n (%) | ||||||
| White | 36 (60) | 15 (25) | 13 (68) | 5 (20) | 23 (56) | 10 (28) |
| African-American | 21 (35) | 43 (70) | 6 (32) | 19 (76) | 15 (37) | 24 (67) |
| Asian | 0 (0) | 1 (2) | 0 | 1 (4) | 0 | 0 |
| Multiple/biracial | 3 (5) | 2 (3) | 0 | 0 (0) | 3 (7) | 2 (6) |
| Hispanic ethnicity, n (%) | 2 (3) | 0 (0) | 0 (0%) | 0 (0) | 2 (5) | 0 (0) |
| Birth weight, mean (SD), g | 895 (215) | 903 (245) | 897 (195) | 851 (282) | 895 (226) | 939 (213) |
| Gestational age, mean (SD), weeks | 26.2 (1.4) | 26.2 (1.4) | 25.8 (1.1) | 25.8 (1.4) | 26.4 (1.5) | 26.5 (1.4) |
| Gestational age strata, n (%) | ||||||
| 240–266 weeks | 40 (67) | 43 (70) | 16 (84) | 20 (80) | 24 (59) | 23 (64) |
| 270–286 weeks | 20 (33) | 18 (30) | 3 (16) | 5 (20) | 17 (41) | 13 (36) |
| SGA, n (%) | 2 (3) | 1 (2) | 0 (0) | 1 (4) | 2 (5) | 0 (0) |
| Preterm labour, n (%) | 47 (78) | 49 (80) | 17 (89) | 18 (72) | 30 (73) | 31 (86) |
| PPROM, n (%) | 23 (38) | 29 (48) | 9 (47) | 17 (68) | 14 (34) | 12 (33) |
| Duration rupture of membranes, n (%) | ||||||
| <1 hour | 36 (60) | 29 (48) | 9 (47) | 7 (28) | 27 (66) | 22 (61) |
| ≥1 hour | 22 (37) | 29 (48) | 9 (47) | 16 (64) | 13 (32) | 13 (36) |
| Unknown | 2 (3) | 3 (5) | 1 (5) | 2 (8) | 1 (2) | 1 (3) |
| Maternal Pe-eclampsia, n (%) | 0 (0) | 2 (3) | 0 (0) | 1 (4) | 0 (0) | 1 (3) |
| Antenatal steroids, n (%) | 51 (85) | 48 (79) | 16 (84) | 19 (76) | 35 (85) | 29 (81) |
| Maternal macrolide, n (%) | ||||||
| Erythromycin | 10 (17) | 11 (18) | 4 (21) | 8 (32) | 6 (15) | 3 (8) |
| Azithromycin | 9 (15) | 9 (15) | 2 (11) | 1 (4) | 7 (17) | 8 (22) |
| Both | 1 (2) | 0 | 0 (0) | 0 | 1 (2) | 0 (0) |
| Neither | 40 (67) | 41 (67) | 13 (68) | 16 (64) | 27 (66) | 25 (69) |
| Route of delivery, n (%) | ||||||
| SVD | 27 (45) | 27 (44) | 9 (47) | 13 (52) | 18 (44) | 14 (39) |
| C/S | 33 (55) | 34 (56) | 10 (53) | 12 (48) | 23 (56) | 22 (61) |
| Apgar 1 min, median (IQR) | 5 (3,7) | 4 (2,6) | 4 (2,8) | 4 (2,5) | 5 (3,7) | 5 (2.5 to 6.5) |
| Apgar 5 min, median (IQR) | 7 (6,8) | 7 (6,8) | 6.5 (5,8) | 6 (6,8) | 7 (6,8) | 7 (5.5 to 8) |
| Respiratory support at enrolment, n (%) | ||||||
| None | 2 (3) | 1 (2) | 1 (5) | 0 (0) | 1 (2) | 1 (3) |
| Non-invasive* | 28 (47) | 34 (56) | 10 (53) | 15 (60) | 18 (44) | 19 (53) |
| Invasive† | 30 (50) | 26 (43) | 8 (42) | 10 (40) | 22 (54) | 16 (44) |
| Duration IMV at enrolment, median (IQR), hours | 24.9 | 29 | 20.5 | 30.9 | 26.5 | 22.2 |
| (10.3,52.3) | (15.0,46.8) | (0.3,53.0) | (21.1,49.3) | (12,49.2) | (10.5,46.4) | |
| Effective FiO2 at enrolment, median (IQR) | 0.24 | 0.25 | 0.26 | 0.27 | 0.22 | 0.25 |
| (0.21,0.28) | (0.21,0.33) | (0.21,0.30) | (0.21,0.30) | (0.21,0.27) | (0.21,0.36) | |
| Postnatal age at time of first dose, mean (SD), hours | 58.5 (23.1) | 56.2 (19.4) | 58.3 (24.1) | 50.4 (18.7) | 58.5 (22.9) | 60.3 (19.0) |
| Ureaplasma spp. respiratory colonisation, n (%) | 19 (32) | 25 (41) | 19 (100) | 25 (100) | N/A | N/A |
| U. parvum | 14 (23) | 19 (31) | 14 (74) | 19 (76) | ||
| U. urealyticum | 3 (5) | 4 (7) | 3 (16) | 4 (16) | ||
| Both species | 1 (2) | 2 (3) | 1 (5) | 2 (8) | ||
| Untyped | 1 (2) | 0 (0) | 1 (5) | 0 (0) | ||
*Non-invasive ventilation included oxyhood, low flow nasal cannula, high flow nasal cannula, nasal continuous positive pressure and nasal intermittent positive pressure ventilation.
†Invasive ventilation included synchronised intermittent mechanical ventilation, high frequency oscillatory ventilation and high frequency jet ventilation.
AZM, azithromycin; C/S, caesarean section; FiO2, fractional inspired oxygen; IMV, intermittent mandatory ventilation; PPROM, preterm premature rupture of membranes; SGA, small for gestational age; SVD, spontaneous vaginal delivery.