Table 5.
Associations between number of preterm deliveries and all cause mortality in women with two or more singleton deliveries
| Deaths | Rate* | Hazard ratio (95% CI)† | P value | |
|---|---|---|---|---|
| 0-44 years after first delivery | ||||
| 0 preterm | 29 845 | 95.7 | Reference | — |
| 1 preterm | 4000 | 130.0 | 1.27 (1.23 to 1.31) | <0.001 |
| ≥2 preterm | 1074 | 161.5 | 1.61 (1.51 to 1.71) | <0.001 |
| Per additional preterm delivery | — | — | 1.24 (1.21 to 1.27) | <0.001 |
| <10 years after first delivery | ||||
| 0 preterm | 1883 | 15.3 | Reference | — |
| 1 preterm | 286 | 24.0 | 1.38 (1.22 to 1.57) | <0.001 |
| ≥2 preterm | 43 | 16.8 | 0.92 (0.68 to 1.24) | 0.57 |
| Per additional preterm delivery | — | — | 1.13 (1.04 to 1.24) | 0.005 |
| 10-19 years after first delivery | ||||
| 0 preterm | 5227 | 56.6 | Reference | — |
| 1 preterm | 746 | 81.1 | 1.31 (1.21 to 1.41) | <0.001 |
| ≥2 preterm | 207 | 103.4 | 1.62 (1.41 to 1.86) | <0.001 |
| Per additional preterm delivery | — | — | 1.25 (1.19 to 1.31) | <0.001 |
| 20-44 years after first delivery | ||||
| 0 preterm | 22 735 | 235.8 | Reference | — |
| 1 preterm | 2968 | 306.9 | 1.25 (1.20 to 1.30) | <0.001 |
| ≥2 preterm | 824 | 395.1 | 1.65 (1.54 to 1.77) | <0.001 |
| Per additional preterm delivery | — | — | 1.24 (1.21 to 1.27) | <0.001 |
*
Mortality rate per 100 000 person years.
†
Adjusted for maternal age, year of delivery, parity, education, employment, income, region of origin, body mass index, smoking, pre-eclampsia, other hypertensive disorders, diabetes, asthma, rheumatoid arthritis, and depression.