Table 4.
Interventions for healthy women with low risk pregnancies by their planned place of birth at start of care in labour
| Intervention and planned place of birth | No of events/births | Incidence of events/100 (99% CI)* | Odds ratio (99% CI)* | |
|---|---|---|---|---|
| Unadjusted | Adjusted† | |||
| Spontaneous vertex birth: | 54 798/64 483 | 76.4 (73.8 to 78.7) | (n=62 592)‡ | |
| Obstetric unit | 14 645/19 688 | 73.8 (71.1 to 76.4) | 1.00 | 1.00 |
| Home | 15 590/16 825 | 92.8 (91.7 to 93.7) | 4.49 (3.67 to 5.49) | 3.61 (2.97 to 4.38) |
| Freestanding midwifery unit | 10 150/11 280 | 90.7 (89.1 to 92.0) | 3.45 (2.76 to 4.31) | 3.38 (2.70 to 4.25) |
| Alongside midwifery unit | 14 413/16 690 | 85.9 (83.7 to 87.9) | 2.16 (1.74 to 2.70) | 2.22 (1.76 to 2.81) |
| Vaginal breech birth: | 171/64 483 | 0.2 (0.2 to 0.3) | (n=62 592)‡ | |
| Obstetric unit | 43/19 688 | 0.2 (0.1 to 0.3) | 1.00 | 1.00 |
| Home | 63/16 825 | 0.4 (0.3 to 0.5) | 1.83 (0.97 to 3.45) | 2.13 (1.15 to 3.96) |
| Freestanding midwifery unit | 39/11 280 | 0.4 (0.2 to 0.6) | 1.79 (0.86 to 3.72) | 2.00 (1.00 to 3.99) |
| Alongside midwifery unit | 26/16 690 | 0.2 (0.1 to 0.3) | 0.94 (0.43 to 2.07) | 0.94 (0.44 to 2.04) |
| Ventouse delivery: | 2953/64 483 | 7.3 (5.9 to 9.0) | (n=62 592)‡ | |
| Obstetric unit | 1535/19 688 | 8.1 (6.4 to 10.1) | 1.00 | 1.00 |
| Home | 342/16 825 | 2.0 (1.6 to 2.5) | 0.24 (0.17 to 0.33) | 0.29 (0.21 to 0.40) |
| Freestanding midwifery unit | 321/11 280 | 2.7 (2.0 to 3.5) | 0.31 (0.21 to 0.46) | 0.32 (0.22 to 0.47) |
| Alongside midwifery unit | 755/16 690 | 4.8 (3.6 to 6.2) | 0.57 (0.39 to 0.83) | 0.56 (0.39 to 0.82) |
| Forceps delivery: | 2813/64 483 | 6.2 (5.1 to 7.6) | (n=62 592)‡ | |
| Obstetric unit | 1307/19 688 | 6.8 (5.4 to 8.4) | 1.00 | 1.00 |
| Home | 372/16 825 | 2.1 (1.8 to 2.5) | 0.30 (0.22 to 0.40) | 0.43 (0.32 to 0.57) |
| Freestanding midwifery unit | 365/11 280 | 2.9 (2.3 to 3.7) | 0.41 (0.29 to 0.58) | 0.45 (0.32 to 0.63) |
| Alongside midwifery unit | 769/16 690 | 4.7 (3.5 to 6.4) | 0.68 (0.45 to 1.01) | 0.70 (0.46 to 1.05) |
| Intrapartum caesarean section: | 3748/64 483 | 9.9 (8.4 to 11.5) | (n=62 592)‡ | |
| Obstetric unit | 2158/19 688 | 11.1 (9.5 to 13.0) | 1.00 | 1.00 |
| Home | 458/16 825 | 2.8 (2.3 to 3.4) | 0.23 (0.17 to 0.30) | 0.31 (0.23 to 0.41) |
| Freestanding midwifery unit | 405/11 280 | 3.5 (2.8 to 4.2) | 0.28 (0.21 to 0.37) | 0.32 (0.24 to 0.42) |
| Alongside midwifery unit | 727/16 690 | 4.4 (3.5 to 5.5) | 0.37 (0.28 to 0.49) | 0.39 (0.29 to 0.53) |
| Third or fourth degree perineal trauma: | 1737/64 354 | 3.1 (2.7 to 3.6) | (n=62 482)‡ | |
| Obstetric unit | 625/19 638 | 3.2 (2.7 to 3.7) | 1.00 | 1.00 |
| Home | 318/16 800 | 1.9 (1.6 to 2.3) | 0.58 (0.45 to 0.76) | 0.77 (0.57 to 1.05) |
| Freestanding midwifery unit | 259/11 262 | 2.3 (1.9 to 2.9) | 0.72 (0.56 to 0.94) | 0.78 (0.58 to 1.05) |
| Alongside midwifery unit | 535/16 654 | 3.2 (2.6 to 4.0) | 1.02 (0.77 to 1.34) | 1.04 (0.79 to 1.38) |
| Blood transfusion: | 545/64 044 | 1.2 (0.9 to 1.4) | (n=62 219)‡ | |
| Obstetric unit | 241/19 579 | 1.2 (1.0 to 1.6) | 1.00 | 1.00 |
| Home | 101/16 687 | 0.6 (0.5 to 0.9) | 0.54 (0.36 to 0.80) | 0.72 (0.47 to 1.12) |
| Freestanding midwifery unit | 67/11 230 | 0.5 (0.4 to 0.7) | 0.42 (0.28 to 0.64) | 0.48 (0.32 to 0.73) |
| Alongside midwifery unit | 136/16 548 | 0.9 (0.7 to 1.2) | 0.72 (0.52 to 1.00) | 0.75 (0.55 to 1.02) |
| Admission to a higher level of care: | 281/64 538 | 0.6 (0.4 to 1.0) | (n=62 635)‡ | |
| Obstetric unit | 117/19 706 | 0.6 (0.3 to 1.1) | 1.00 | 1.00 |
| Home | 58/16 840 | 0.4 (0.2 to 0.6) | 0.61 (0.29 to 1.27) | 0.77 (0.36 to 1.65) |
| Freestanding midwifery unit | 24/11 282 | 0.2 (0.1 to 0.3) | 0.27 (0.11 to 0.69) | 0.32 (0.13 to 0.84) |
| Alongside midwifery unit | 82/16 710 | 0.7 (0.3 to 1.5) | 1.14 (0.43 to 3.03) | 1.17 (0.46 to 2.99) |
| Syntocinon augmentation: | 8078/64 174 | 20.9 (18.7 to 23.3) | (n=62 314)‡ | |
| Obstetric unit | 4549/19 483 | 23.5 (21.1 to 26.2) | 1.00 | 1.00 |
| Home | 943/16 794 | 5.4 (4.8 to 6.1) | 0.19 (0.15 to 0.23) | 0.25 (0.21 to 0.31) |
| Freestanding midwifery unit | 878/11 238 | 7.1 (6.0 to 8.5) | 0.25 (0.19 to 0.32) | 0.26 (0.20 to 0.33) |
| Alongside midwifery unit | 1708/16 659 | 10.3 (8.9 to 11.8) | 0.38 (0.30 to 0.46) | 0.37 (0.30 to 0.46) |
| Immersion in water for pain relief: | 17 674/64 086 | 13.4 (10.5 to 16.9) | (n=62 214)‡ | |
| Obstetric unit | 1836/19 680 | 9.1 (6.4 to 12.6) | 1.00 | 1.00 |
| Home | 5523/16 443 | 33.3 (30.1 to 36.6) | 4.91 (3.31 to 7.28) | 5.40 (3.64 to 8.00) |
| Freestanding midwifery unit | 5253/11 270 | 45.7 (35.6 to 56.3) | 8.27 (4.72 to 14.50) | 8.36 (4.76 to 14.69) |
| Alongside midwifery unit | 5062/16 693 | 30.2 (23.4 to 38.1) | 4.21 (2.54 to 6.99) | 4.46 (2.71 to 7.34) |
| Epidural or spinal analgesia: | 10 950/64 287 | 27.6 (24.6 to 30.8) | (n=62 434)‡ | |
| Obstetric unit | 5817/19 576 | 30.7 (27.5 to 34.2) | 1.00 | 1.00 |
| Home | 1418/16 799 | 8.3 (7.3 to 9.4) | 0.20 (0.17 to 0.25) | 0.25 (0.20 to 0.31) |
| Freestanding midwifery unit | 1251/11 251 | 10.6 (9.1 to 12.3) | 0.27 (0.21 to 0.33) | 0.27 (0.22 to 0.34) |
| Alongside midwifery unit | 2464/16 661 | 15.3 (13.2 to 17.7) | 0.41 (0.32 to 0.51) | 0.40 (0.32 to 0.50) |
| General anaesthesia: | 522/64 019 | 1.3 (1.0 to 1.6) | (n=62 177)‡ | |
| Obstetric unit | 285/19 421 | 1.5 (1.1 to 1.8) | 1.00 | 1.00 |
| Home | 77/16 714 | 0.5 (0.3 to 0.6) | 0.31 (0.21 to 0.47) | 0.40 (0.26 to 0.60) |
| Freestanding midwifery unit | 61/11 243 | 0.5 (0.3 to 0.8) | 0.36 (0.21 to 0.62) | 0.40 (0.23 to 0.69) |
| Alongside midwifery unit | 99/16 641 | 0.6 (0.4 to 0.9) | 0.44 (0.29 to 0.67) | 0.47 (0.31 to 0.72) |
| No active management of 3rd stage: | 11 413/64 074 | 8.5 (6.9 to 10.4) | (n=62 210)‡ | |
| Obstetric unit | 1188/19 683 | 6.1 (4.6 to 8.1) | 1.00 | 1.00 |
| Home | 5092/16 428 | 31.3 (27.6 to 35.2) | 6.99 (4.96 to 9.84) | 6.75 (4.74 to 9.60) |
| Freestanding midwifery unit | 2568/11 271 | 22.1 (15.8 to 30.0) | 4.39 (2.65 to 7.28) | 4.42 (2.67 to 7.31) |
| Alongside midwifery unit | 2565/16 692 | 14.1 (10.2 to 19.1) | 2.50 (1.56 to 3.99) | 2.46 (1.55 to 3.91) |
| Episiotomy: | 7806/64 312 | 17.8 (16.0 to 19.6) | (n=62 422)‡ | |
| Obstetric unit | 3780/19 678 | 19.3 (17.4 to 21.4) | 1.00 | 1.00 |
| Home | 933/16 670 | 5.4 (4.8 to 6.1) | 0.24 (0.20 to 0.29) | 0.33 (0.28 to 0.39) |
| Freestanding midwifery unit | 995/11 275 | 8.6 (7.3 to 10.1) | 0.39 (0.31 to 0.49) | 0.40 (0.32 to 0.51) |
| Alongside midwifery unit | 2098/16 689 | 13.1 (11.4 to 14.9) | 0.63 (0.51 to 0.77) | 0.62 (0.50 to 0.77) |
*Weighted to reflect each unit’s duration of participation and probability of being sampled; confidence intervals take account of the clustered nature of the data.
†Adjusted for maternal age, ethnic group, understanding of English, marital or partner status, body mass index, deprivation score quintile, previous pregnancies, and weeks of gestation.
‡Restricted to women who were not missing any potential confounder data.