Mode of birth, intervention rates and perineal outcomes by planned place of birth
| Intervention and planned place of birth | No. of events | No. of births | Incidence of events (%) | Unadjusted OR | Adjusted OR* |
| Normal vaginal birth | 992 118 | 1 251 420 | 79.3 | ||
| Hospital | 920 514 | 1 171 703 | 78.6 | 1 | 1 |
| Birth centre | 63 790 | 71 505 | 89.2 | 2.26 (2.19–2.33) | 2.72 (2.63–2.81) |
| Home | 7814 | 8212 | 95.2 | 5.36 (4.69–6.12) | 5.91 (5.15–6.78) |
| Vacuum extraction | 88 586 | 1 251 420 | 7.1 | ||
| Hospital | 85 975 | 1 171 703 | 7.3 | 1 | 1 |
| Birth centre | 2503 | 71 505 | 3.5 | 0.44 (0.42–0.47) | 0.42 (0.40–0.44) |
| Home | 108 | 8212 | 1.3 | 0.19 (0.15–0.24) | 0.18 (0.14–0.24) |
| Forceps birth | 56 332 | 1 251 420 | 4.5 | ||
| Hospital | 54 451 | 1 171 703 | 4.6 | 1 | 1 |
| Birth centre | 1820 | 71 505 | 2.5 | 0.54 (0.50–0.57) | 0.54 (0.50–0.58) |
| Home | 61 | 8212 | 0.7 | 0.15 (0.11–0.21) | 0.21 (0.14–0.31) |
| Intrapartum caesarean section | 94 303 | 1 251 420 | 7.5 | ||
| Hospital | 91 238 | 1 171 703 | 7.8 | 1 | 1 |
| Birth centre | 2871 | 71 505 | 4 | 0.50 (0.47–0.52) | 0.45 (0.43–0.48) |
| Home | 194 | 8212 | 2.4 | 0.29 (0.24–0.35) | 0.29 (0.24–0.35) |
| Mode of birth not stated | 20 081 | 1 251 420 | 1.6 | ||
| Hospital | 19 525 | 1 171 703 | 1.7 | 1 | 1 |
| Birth centre | 521 | 71 505 | 0.7 | 0.43 (0.39–0.49) | 0.41 (0.36–0.46) |
| Home | 35 | 8212 | 0.4 | 0.25 (0.16–0.39) | 0.26 (0.17–0.41) |
| Oxytocin augmentation | 199 302 | 1 251 420 | 15.9 | ||
| Hospital | 193 229 | 1 171 703 | 16.5 | 1 | 1 |
| Birth centre | 5790 | 71 505 | 8.1 | 0.45 (0.43–0.46) | 0.41 (0.40–0.43) |
| Home | 283 | 8212 | 3.4 | 0.18 (0.15–0.21) | 0.19 (0.16–0.22) |
| Epidural or spinal analgesia for labour | 166 746 | 1 251 420 | 13.3 | ||
| Hospital | 161 796 | 1 171 703 | 13.8 | 1 | 1 |
| Birth centre | 4675 | 71 505 | 6.5 | 0.44 (0.42–0.45) | 0.41 (0.39–0.43) |
| Home | 275 | 8212 | 3.3 | 0.22 (0.18–0.25) | 0.22 (0.19–0.26) |
| Intact perineum† | 308 232 | 1 157 117 | 26.6 | ||
| Hospital | 283 887 | 1 080 465 | 26.3 | 1 | 1 |
| Birth centre | 20 562 | 68 634 | 30 | 1.20 (1.17–1.23) | 1.39 (1.36–1.43) |
| Home | 3783 | 8018 | 47.2 | 2.51 (2.37–2.66) | 2.72 (2.56–2.90) |
| Episiotomy† | 193 171 | 1 157 117 | 16.7 | ||
| Hospital | 187 276 | 1 080 465 | 17.3 | 1 | 1 |
| Birth centre | 5688 | 68 634 | 8.3 | 0.43 (0.42–0.45) | 0.37 (0.36–0.39) |
| Home | 207 | 8018 | 2.6 | 0.13 (0.11–0.15) | 0.13 (0.10–0.15) |
| Third or fourth degree perineal trauma | 23 165 | 1 157 117 | 2 | ||
| Hospital†‡ | 21 454 | 1 080 465 | 2 | 1 | 1 |
| Birth centre | 1641 | 68 634 | 2.4 | 1.21 (1.13–1.29) | 1.17 (1.09–1.25) |
| Home | 70 | 8018 | 0.9 | 0.43 (0.32–0.59) | 0.53 (0.36–0.73) |
Cases with missing data were not included in rates or regression calculations.
Variables on mode of birth and intervention are as defined by each state or territory.
*Logistic regression adjusted for maternal age, country of birth, gestational age and parity at 99% CI.
†Denominator=excluded caesarean section.
‡Included episiotomy extensions.