Outcome | No. (%) of participants* | P value† | ||

Never intubated (no TA specimen) (n=47) | TA Ureaplasma negative(n=52) | TA Ureaplasma positive(n=21) | ||

Baseline characteristics | ||||

Male, n (%) | 24 (51) | 25 (48) | 9 (43) | 0.88 |

Non-white race, n (%) | 34 (72) | 24 (46) | 12 (57) | 0.12 |

Birth weight, mean (SD), g | 994 (244) | 854 (207) | 805 (188) | 0.004 |

Gestational age, mean (SD), weeks | 26.9 (1.2) | 26.0 (1.4) | 25.4 (1.0) | <0.001 |

Gestational age strata, n (%) | ||||

24^{0}–26^{6} weeks | 24 (51) | 39 (75) | 19 (90) | 0.004 |

27^{0}–28^{6} weeks | 23 (48) | 13 (25) | 2 (10) | |

Preterm labour, n (%) | 37 (79) | 40 (77) | 18 (86) | 0.62 |

PPROM | 23 (49) | 16 (31) | 13 (62) | 0.03 |

Antenatal steroids | 39 (83) | 42 (81) | 17 (81) | 0.95 |

Maternal macrolide exposure | 20 (43) | 13 (25) | 6 (29) | 0.26 |

C/S delivery | 28 (60) | 29 (56) | 9 (43) | 0.40 |

Admission WCC × 10^{3}, mean (SD) | 14.5 (9.4) | 11.3 (7.2) | 21.4 (17.8) | 0.05 |

Ureaplasma spp. respiratory colonisation, n (%) | 18 (38) | 5 (10) | 21 (100) | 0.01 |

Primary and secondary outcomes | ||||

Ureaplasma-free survival, n (%) | 37 (78) | 46 (88) | 8 (38) | 0.002 |

Survival, n (%) | 47 (100) | 47 (90) | 15 (71) | <0.001 |

Ureaplasma clearance post-treatment, n (%) | 8/18 (44) | 4/5 (8%) | 11/21 (52) | 0.44 |

Survival free of physiological BPD, n (%)‡ | 37/45 (82) | 22/51 (43) | 7 (33) | <0.001 |

Physiological BPD, n (%)‡§ | 8/45 (18) | 26/48 (54) | 9/16 (56) | 0.001 |

Modified Shennan BPD, n (%)§ | 14 (29) | 28/49 (57) | 9/16 (56) | 0.02 |

Moderate-severe BPD, n (%)§ | 14 (29) | 30/49 (61) | 9/16 (56) | 0.009 |

Discharge home, n (%) | 33 (70) | 28 (54) | 7 (33) | 0.02 |

Postnatal steroids exposure, n (%) | 3 (6) | 16 (31) | 10 (48) | 0.001 |

Passed hearing screen, n (%)¶ | 44/46 (96) | 45/46 (98) | 12/15 (80) | 0.27 |

Total duration IMV, median (IQR)¶** | 1 (1–2) | 19.5 (9.5–55) | 44 (24 to –) | <0.001 |

Total duration supplemental oxygen, median (IQR)‡** | 38 (15–64) | 85 (59–125) | 135 (77 to –) | <0.001 |

Duration hospitalisation, median (IQR)¶** | 71 (56–87) | 99 (81–142) | 110 (76 to –) | <0.001 |

*One surviving participant with moderate-severe BPD who was discharged home was intubated but had no TA specimens and is not included in this analysis.

†P values for binary outcomes are based on a score test from generalised estimating equations to account for correlations between twins, or Fisher’s exact test when one of the cell sizes has an expectation of less than 5. P values for quantitative outcomes are based on non-parametric tests using multiple outputation to account for correlations between twins.

‡Excludes three participants who could not be classified with respect to physiological BPD.

§Excludes eight participants who died prior to BPD assessment.

¶Based on only those who survived until discharge but excludes two survivors who did not have a hearing screen.

**In computing the median and IQR, those who died are included as having the worst outcomes. For the TA

*Ureaplasma*-positive participants, more than 25% died, so it was not possible to specify the actual 75th percentile.BPD, bronchopulmonary dysplasia; C/S, caesarean section; IMV, intermittent mandatory ventilation; PPROM, preterm premature rupture of membranes; TA, tracheal aspirate; WCC, white cell count.