Table 3 Incidence rates of pregnancy by age at conception
| Â | Total at risk | Number of new pregnancies | Pregnancies per 1000 women | Number of person years of follow up | Incidence rate per 1000 woman years (95% CI) |
|---|---|---|---|---|---|
Overall | 8024a | 448 | 55.8 | 20,466.4 | 21.9 (20.0, 24.0) |
Age at conception | |||||
 < 15 | 4563 | 15 | 3.3 | 11,740.8 | 1.3 (0.8, 2.2) |
 15 | 2202 | 28 | 12.7 | 1901.6 | 14.7 (10.1, 21.3) |
 16 | 1984 | 42 | 21.2 | 1608.8 | 26.1 (19.3, 35.3) |
 17 | 2017 | 66 | 32.7 | 1502.9 | 43.9 (34.5, 55.9) |
 18 | 2220 | 127 | 57.2 | 1450.7 | 87.5 (73.5, 104.1) |
 19 | 2824 | 170 | 60.2 | 2261.6 | 64.7(64.7, 87.4) |