Table 2

 Demographic, obstetric, and neonatal characteristics of cohort by neonatal respiratory morbidity

No RDS/TTN, n = 170 909RDS/TTN, n = 2230p*
2 test or Mann-Whitney U test, as appropriate.
†Although the medians and IQR do not differ, the groups were different due to less than 1 unit differences in these variables between the two groups.
IQR, inter-quartile range; RDS, respiratory distress syndrome; TTN, transient tachypnoea of the newborn.
MaternalAge (years)Median (IQR)28 (24–31)28 (24–31)0.007†
characteristicsParityNulliparous75 960 (44.4)1066 (47.8)0.002
Multiparous94 949 (55.6)1164 (52.2)
Deprivation category, n (%)1 (least deprived)9113 (5.3)112 (5.0)0.47
222 797 (13.3)280 (12.6)
334 091 (10.0)456 (20.5)
441 606 (24.3)547 (24.5)
527 895 (16.3)382 (17.1)
621 685 (12.7)258 (11.6)
7 (most deprived)13 722 (8.0)195 (8.7)
Height (cm)Median (IQR)162 (157–166)162 (157–166)<0.001†
SmokingNon-smoker103 259 (60.4)1421 (63.7)0.001
Status, n (%)Ex-smoker14 140 (8.3)192 (8.6)
Smoker53 510 (31.3)617 (27.7)
Maternal asthma385 (0.2)9 (0.4)0.08
ObstetricMode of delivery, n (%)Vaginal birth146 404 (85.7)1366 (61.3)<0.001
characteristicsEmergency caesarean14 718 (8.6)411 (18.4)<0.001
Elective caesarean9787 (5.7)453 (20.3)<0.001
Gestational age at delivery (weeks)Median (IQR)40 (39–41)40 (38–41)<0.001
Onset of labour, n (%)Spontaneous129 064 (75.5)1686 (75.6)0.92
Induced41 845 (24.5)544 (24.4)
NeonatalSex, n (%)Female84 536 (49.5)757 (34.0)<0.001
characteristicsMale86 373 (50.5)1473 (66.1)
Birth weight (g)Median (IQR)3440 (3120–3760)3489 (3100–3860)<0.001
5 min<72340 (1.4)114 (5.1)<0.001
Apgar, n (%)7–10168 569 (98.6)2116 (94.9)