Perinatal outcomes by maternal age in low-risk women aged 16 and over
| OU | Non-OU | |||||
|---|---|---|---|---|---|---|
| Events/births | Weighted* | Events/births | Weighted* | |||
| Age (years) | n/N | % | (95% CI) | n/N | % | (95% CI) |
| Nulliparous | ||||||
| 16–19 | 39/1260 | 3.2 | (2.2 to 4.5) | 31/1553 | 2.9 | (1.9 to 4.4) |
| 20–24 | 89/2610 | 3.5 | (2.5 to 5.0) | 94/3700 | 2.4 | (1.9 to 3.2) |
| 25–29 | 92/3026 | 3.3 | (2.6 to 4.0) | 123/5357 | 2.1 | (1.7 to 2.8) |
| 30–34 | 101/2340 | 4.2 | (3.1 to 5.6) | 128/4918 | 3.0 | (2.2 to 4.0) |
| 35–39 | 37/962 | 3.9 | (2.8 to 5.4) | 65/1999 | 3.0 | (2.1 to 4.1) |
| 40+ | 10/149 | 7.5 | (3.4 to 15.7) | 8/195 | 3.9 | (1.0 to 14.0) |
| Total | 368/10 347 | 3.7 | (2.9 to 4.6) | 449/17 722 | 2.6 | (2.2 to 3.1) |
| Multiparous | ||||||
| 16–19 | 6/179 | 3.0 | (1.4 to 6.4) | 5/337 | 1.7 | (0.6 to 4.6) |
| 20–24 | 26/1519 | 1.8 | (1.2 to 2.7) | 43/3489 | 1.3 | (0.8 to 2.0) |
| 25–29 | 41/2547 | 1.6 | (1.2 to 2.3) | 73/7032 | 1.1 | (0.8 to 1.6) |
| 30–34 | 50/2578 | 2.0 | (1.5 to 2.6) | 111/8468 | 1.2 | (1.0 to 1.5) |
| 35–39 | 33/1594 | 2.1 | (1.3 to 3.3) | 88/5761 | 1.6 | (1.2 to 2.2) |
| 40+ | 7/345 | 2.1 | (0.9 to 4.6) | 20/978 | 2.3 | (1.3 to 4.1) |
| Total | 163/8762 | 1.9 | (1.5 to 2.4) | 340/26 065 | 1.3 | (1.1 to 1.6) |
*Percentages are weighted to take account of 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.
OU, obstetric unit.