Table 3.
Primary outcome* for babies of heathy women with low risk pregnancies by their planned place of birth at start of care in labour. Categorised by parity for all women and restricted to those without complicating conditions at start of care in labour
| Planned place of birth | No of events/births | Incidence of events/1000 (95% CI)† | Odds ratio (95% CI)† | |
|---|---|---|---|---|
| Unadjusted | Adjusted‡ | |||
| All women | ||||
| Total: | 250/63 827 | 4.3 (3.3 to 5.5) | (n=62 036)§ | |
| Obstetric unit | 81/19 551 | 4.4 (3.2 to 5.9) | 1.00 | 1.00 |
| Home | 70/16 553 | 4.2 (3.2 to 5.4) | 0.96 (0.65 to 1.42) | 1.16 (0.76 to 1.77) |
| Freestanding midwifery unit | 41/11 199 | 3.5 (2.5 to 4.9) | 0.82 (0.52 to 1.28) | 0.92 (0.58 to 1.46) |
| Alongside midwifery unit | 58/16 524 | 3.6 (2.6 to 4.9) | 0.84 (0.54 to 1.30) | 0.92 (0.60 to 1.39) |
| Nulliparous women¶: | 153/28 443 | 5.3 (4.0 to 7.0) | (n=27 669)§ | |
| Obstetric unit | 52/10 541 | 5.3 (3.9 to 7.3) | 1.00 | 1.00 |
| Home | 39/4488 | 9.3 (6.5 to 13.1) | 1.76 (1.10 to 2.82) | 1.75 (1.07 to 2.86) |
| Freestanding midwifery unit | 24/5158 | 4.5 (2.8 to 7.1) | 0.85 (0.49 to 1.48) | 0.91 (0.52 to 1.60) |
| Alongside midwifery unit | 38/8256 | 4.7 (3.1 to 7.2) | 0.90 (0.53 to 1.54) | 0.96 (0.58 to 1.61) |
| Multiparous women¶: | 97/35 289 | 3.1 (2.2 to 4.5) | (n=34 367)§ | |
| Obstetric unit | 29/8980 | 3.3 (2.2 to 5.0) | 1.00 | 1.00 |
| Home | 31/12 050 | 2.3 (1.6 to 3.2) | 0.70 (0.40 to 1.21) | 0.72 (0.41 to 1.27) |
| Freestanding midwifery unit | 17/6025 | 2.7 (1.6 to 4.6) | 0.86 (0.44 to 1.69) | 0.91 (0.46 to 1.80) |
| Alongside midwifery unit | 20/8234 | 2.4 (1.4 to 4.3) | 0.77 (0.38 to 1.57) | 0.81 (0.40 to 1.62) |
| Women without complicating conditions at start of care in labour | ||||
| Total: | 199/57 127 | 3.1 (2.4 to 4.0) | (n=55 572)§ | |
| Obstetric unit | 48/15 676 | 3.1 (2.2 to 4.2) | 1.00 | 1.00 |
| Home | 62/15 538 | 4.0 (3.0 to 5.3) | 1.34 (0.88 to 2.05) | 1.59 (1.01 to 2.52) |
| Freestanding midwifery unit | 35/10 571 | 3.2 (2.3 to 4.6) | 1.11 (0.69 to 1.77) | 1.22 (0.76 to 1.96) |
| Alongside midwifery unit | 54/15 342 | 3.4 (2.4 to 4.9) | 1.19 (0.74 to 1.91) | 1.26 (0.80 to 1.99) |
| Nulliparous women**: | 121/24 384 | 3.8 (2.8 to 5.1) | (n=23 742)§ | |
| Obstetric unit | 28/8018 | 3.5 (2.4 to 5.1) | 1.00 | 1.00 |
| Home | 36/4063 | 9.5 (6.6 to 13.7) | 2.81 (1.66 to 4.76) | 2.80 (1.59 to 4.92) |
| Freestanding midwifery unit | 22/4785 | 4.5 (2.8 to 7.4) | 1.33 (0.72 to 2.46) | 1.40 (0.74 to 2.65) |
| Alongside midwifery unit | 35/7518 | 4.4 (2.7 to 7.0) | 1.31 (0.71 to 2.39) | 1.38 (0.75 to 2.52) |
| Multiparous women**: | 78/32 662 | 2.5 (1.6 to 3.9) | (n=31 830)§ | |
| Obstetric unit | 20/7637 | 2.6 (1.5 to 4.4) | 1.00 | 1.00 |
| Home | 26/11 461 | 2.0 (1.4 to 2.9) | 0.80 (0.41 to 1.54) | 0.83 (0.44 to 1.58) |
| Freestanding midwifery unit | 13/5772 | 2.2 (1.3 to 3.8) | 0.90 (0.42 to 1.94) | 0.97 (0.46 to 2.04) |
| Alongside midwifery unit | 19/7792 | 2.5 (1.4 to 4.5) | 1.04 (0.47 to 2.30) | 1.09 (0.50 to 2.39) |
*Primary outcome was perinatal mortality and intrapartum related neonatal morbidities (stillbirth after start of care in labour, early neonatal death, neonatal encephalopathy, meconium aspiration syndrome, brachial plexus injury, fractured humerus or clavicle).
†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.
¶Test for statistical interaction between planned place of birth and parity. P values for parity adjusted regression tests of heterogeneity: overall 0.06; pairwise (v obstetric unit) for home 0.01, freestanding midwifery unit 0.99, and alongside midwifery unit 0.69.
**Test for statistical interaction between planned place of birth and parity. P values for parity adjusted regression tests of heterogeneity: overall 0.03; pairwise (v obstetric unit) for home 0.006, freestanding midwifery unit 0.47, and alongside midwifery unit 0.66.