Table 4.
Adverse perinatal outcomes (‘main composite’) for babies of ‘higher risk’ women by parity and planned place of birth
| Events | Total | Weighted* | Unadjusted* | Adjusted*, ** | ||||
|---|---|---|---|---|---|---|---|---|
| n | n | n/1000 | 95% CI | RR | 95% CI | RR | 95% CI | |
| All ‘higher risk’ women (‘population 1’) | ||||||||
| Overall (Wald test for interaction P = 0.64***) | ||||||||
| OU | 215 | 6636 | 34.0 | 26.7–43.2 | 1 | – | 1 | – |
| Home | 25 | 1469 | 15.2 | 9.9–23.2 | 0.45 | 0.27–0.73 | 0.50 | 0.31–0.81 |
| Nulliparous | ||||||||
| OU | 107 | 2503 | 46.0 | 33.2–63.4 | 1 | – | 1 | – |
| Home | 9 | 283 | 27.7 | 12.5–60.3 | 0.60 | 0.26–1.41 | 0.60 | 0.25–1.43 |
| Parous | ||||||||
| OU | 108 | 4133 | 26.8 | 21.6–33.1 | 1 | – | 1 | – |
| Home | 16 | 1186 | 12.3 | 6.8–22.2 | 0.46 | 0.24–0.86 | 0.47 | 0.25–0.88 |
| ‘Higher risk’ women without ‘complicating conditions’ (‘population 2’) | ||||||||
| Overall (Wald test for interaction P = 0.91***) | ||||||||
| OU | 139 | 4711 | 31.1 | 24.3–39.7 | 1 | – | 1 | – |
| Home | 18 | 1310 | 12.4 | 7.3–21.2 | 0.40 | 0.22–0.72 | 0.42 | 0.23–0.76 |
| Nulliparous | ||||||||
| OU | 64 | 1528 | 44.7 | 31.1–63.9 | 1 | – | 1 | – |
| Home | 6 | 248 | 21.1 | 8.5–51.1 | 0.47 | 0.18–1.24 | 0.43 | 0.16–1.16 |
| Parous | ||||||||
| OU | 75 | 3183 | 24.6 | 19.4–31.0 | 1 | – | 1 | – |
| Home | 12 | 1062 | 10.5 | 5.1–21.9 | 0.43 | 0.20–0.93 | 0.41 | 0.18–0.89 |
*
Probability weights are incorporated to account for differences in the probability of a woman being selected for inclusion in the study arising from differences in each unit/trust's period of participation and the stratum-specific probabilities of selection of OUs.
**
Adjusted for maternal age, ethnic group, marital/partner status, BMI in pregnancy, index of multiple deprivation score quintile, gestation at delivery and parity where appropriate.
***
P-value for interaction between parity (nulliparous versus parous) and planned place of birth.