Table 4

Proportions and associations of short and long-term infant outcomes associated with induction of labour for non-medical reasons, New South Wales, Australia 2001–2016 (N=474 652)

474 652 infants210 779 infants primiparous births263 873 infants multiparous births
Proportion N (%)AOR (99% CI)*Proportion n(%)AOR (99% CI)†Proportion n(%)AOR (99% CI)†
Short-term infant outcomes
Admit NICU or special care nursery
 Spontaneous onset of labour26 218 (6.5)Ref.15 222 (8.4)Ref.10 996 (4.9)Ref.
 Induction of labour4712 (6.8) 1.05 (1.01 to 1.10) 2563 (8.6)1.03 (0.98 to 1.10)2149 (5.4)1.05 (0.99 to 1.12)
Asphyxia
 Spontaneous onset of labour3876 (1.0)Ref.2412 (1.3)Ref.1464 (0.7)Ref.
 Induction of labour776 (1.1) 1.19 (1.07 to 1.31) 464 (1.6) 1.17 (1.03 to 1.34) 312 (0.8) 1.19 (1.01 to 1.41)
Apgar score <4
 Spontaneous onset of labour384 (0.1)Ref.237 (0.1)Ref.147 (0.1)Ref.
 Induction of labour70 (0.1)1.07 (0.76 to 1.50)41 (0.1)1.04 (0.66 to 1.62)29 (0.1)1.11 (0.65 to 1.91)
Birth trauma‡
 Spontaneous onset of labour13 387 (3.3)Ref.9444 (5.2)Ref.3943 (1.8)Ref.
 Induction of labour2619 (3.8) 1.15 (1.08 to 1.21) 1714 (5.8) 1.09 (1.02 to 1.17) 905 (2.3) 1.24 (1.13 to 1.37)
Resuscitation§
 Spontaneous onset of labour99 170 (24.5)Ref.52 216 (28.8)Ref.46 954 (21.0)Ref.
 Induction of labour19 959 (28.8) 1.20 (1.17 to 1.23) 9642 (32.5) 1.15 (1.11 to 1.19) 10 317 (25.9) 1.24 (1.20 to 1.28)
Major resuscitation¶
 Spontaneous onset of labour18 805 (4.6)Ref.10 635 (5.9)Ref.8170 (3.6)Ref.
 Induction of labour3976 (5.7) 1.26 (1.20 to 1.32) 2178 (7.3) 1.27 (1.19 to 1.35) 1798 (4.5) 1.23 (1.15 to 1.32)
Respiratory disorders**
 Spontaneous onset of labour16 466 (4.1)Ref.9372 (5.2)Ref.7094 (3.2)Ref.
 Induction of labour3118 (4.5) 1.11 (1.05 to 1.17) 1691 (5.7) 1.11 (1.03 to 1.19) 1427 (3.6) 1.09 (1.01 to 1.18)
Long-term children’s outcomes††
Asthma
 Spontaneous onset of labour12 369 (3.1)Ref.5357 (3.0)Ref.7039 (3.1)Ref.
 Induction of labour1946 (2.8)1.00 (0.94 to 1.07)792 (2.7)1.05 (0.95 to 1.17)1154 (2.9)0.97 (0.89 to 1.06)
Ear, nose and throat infections
 Spontaneous onset of labour19 272 (4.8)Ref.8849 (4.9)Ref.10 423 (4.7)Ref.
 Induction of labour4410 (6.4) 1.28 (1.22 to 1.34) 1709 (5.8) 1.22 (1.14 to 1.31) 2701 (6.8) 1.32 (1.24 to 1.40)
Eczema
 Spontaneous onset of labour3064 (0.8)Ref.1406 (0.8)Ref.1658 (0.7)Ref.
 Induction of labour474 (0.7)0.99 (0.87 to 1.12)181 (0.6)0.87 (0.71 to 1.07)293 (0.7)1.07 (0.91 to 1.27)
Respiratory infections‡‡
 Spontaneous onset of labour63 142 (15.6)Ref.26 595 (14.7)Ref.36 547 (16.3)Ref.
 Induction of labour12 569 (18.1) 1.22 (1.18 to 1.25) 4698 (15.9) 1.20 (1.15 to 1.26) 7871 (19.8) 1.24 (1.19 to 1.28)
Infections§§
 Spontaneous onset of labour21 741 (5.4)Ref.9687 (5.4)Ref.12 054 (5.4)Ref.
 Induction of labour4220 (6.1) 1.14 (1.09 to 1.19) 1775 (6.0) 1.14 (1.06 to 1.22) 2445 (6.2) 1.15 (1.08 to 1.22)
Infant mortality
Neonatal death ≤28 days post partum
 Spontaneous onset of labour82 (0.02)Ref.48 (0.03)Ref.34 (0.02)Ref.
 Induction of labour13 (0.02)0.87 (0.39 to 1.93)6 (0.02)0.65 (0.19 to 2.18)7 (0.02)1.10 (0.37 to 3.26)
Mortality ≥28 days
 Spontaneous onset of labour366 (0.09)Ref.137 (0.08)Ref.229 (0.10)Ref.
 Induction of labour45 (0.06)0.82 (0.54 to 1.24)19 (0.06)0.98 (0.52 to 1.86)26 (0.07)0.72 (0.42 to 1.24)
  • Associations in bold are statistically significant p≤0.01.

  • *Short-term health outcomes are adjusted for maternal characteristics (ie, maternal age, country of birth, socioeconomic status, gestational age, parity), whereas long-term health outcomes are adjusted for maternal characteristics (ie, maternal age, country of birth, socioeconomic status, gestational age, parity) and children’s birth year.

  • †Short-term health outcomes are adjusted for maternal characteristics (ie, maternal age, country of birth, socioeconomic status, gestational age), whereas long-term health outcomes are adjusted for maternal characteristics (ie, maternal age, country of birth, socioeconomic status, gestational age) and children’s birth year.

  • ‡Birth trauma refers to birth trauma to central or peripheral nervous system, birth trauma to scalp, birth trauma to skeleton, intracranial laceration and haemorrhage due to birth trauma.

  • §Resuscitation refers to suction, oxygen therapy, IPPV by bag and mask, intubation and IPPV, external cardiac massage and ventilation.

  • ¶Major resuscitation refers to IPPV by bag and mask, intubation and IPPV, external cardiac massage and ventilation.

  • **Respiratory disorders include admissions to NICU/SCN in the perinatal period related to respiratory distress of newborn, chronic respiratory disease.

  • ††Long-term health outcomes are examined for 474 146 infants, 210 569 first born infants, 2nd–8th 263 577 born infants who were alive during the follow-up period.

  • ‡‡Respiratory infections include admissions related to for example, acute (obstructive) laryngitis, (bacterial) pneumonia.

  • §§Infections include admissions related to, for example, bacterial sepsis, streptococcal sepsis.

  • aOR, adjusted OR; IPPV, Intermittent Positive Pressure Ventilation; NICU, neonatal intensive care unit; SCN, Special Care Nursery.