Relative risk* of stillbirths and combined stillbirths and neonatal deaths among singleton infants with birthweights of at least 2500 g in maternity units of different size
| Size of maternity unit (No of births per year) | Deliveries (n) | Stillbirths† | Combined stillbirths and neonatal deaths‡ | ||||
|---|---|---|---|---|---|---|---|
| Relative risk* (95 % CI) | Relative risk* (95 % CI) | ||||||
| ⩽100 | 26 538 | 0.7 (0.6–1.0) | 1.2 (1.0–1.4) | ||||
| 101–500 | 198 030 | 1.0 (0.9–1.2) | 1.3 (1.1–1.4) | ||||
| 501–1000 | 204 261 | 1.0 (0.9–1.1) | 1.2 (1.1–1.3) | ||||
| 1001–2000 | 404 635 | 1.0 (0.9–1.1) | 1.2 (1.1–1.3) | ||||
| 2001–3000 | 182 437 | 1.0 (ref.) | 1.0 (ref.) | ||||
| >3000 | 241 698 | 1.1 (0.9–1.2) | 1.3 (1.1–1.4) | ||||
4-150 Relative risks were approximated by odds ratios in logistic regression models adjusted for year of birth, congenital anomalies, maternal disease during pregnancy, breech presentation, multiparas, hydramnios or oligohydramnios, premature rupture of the membranes and placenta previa.
4-151 There was not an overall significant difference in mortality between maternity units with a p value of 0.17.
4-152 There was an overall significant difference in mortality between maternity units with a p value of less than 0.0001.