Table 3.
Co-sibling analyses of length of pregnancy in women and all cause mortality
| Deaths | Hazard ratio (95% CI)* | P value | |
|---|---|---|---|
| 0-44 years after delivery | |||
| Preterm (<37 weeks) | 5018 | 1.39 (1.30 to 1.48) | <0.001 |
| Early term (37-38 weeks) | 10 077 | 1.10 (1.05 to 1.16) | <0.001 |
| Full term (39-41 weeks) | 19 738 | Reference | — |
| Per additional week (trend) | — | 0.95 (0.94 to 0.96) | <0.001 |
| <10 years after delivery | |||
| Preterm (<37 weeks) | 940 | 1.68 (1.20 to 2.35) | 0.003 |
| Early term (37-38 weeks) | 1694 | 1.20 (0.93 to 1.56) | 0.17 |
| Full-term (39-41 weeks) | 3047 | Reference | — |
| Per additional week (trend) | — | 0.92 (0.88 to 0.96) | <0.001 |
| 10-19 years after delivery | |||
| Preterm (<37 weeks) | 1402 | 1.46 (1.19 to 1.80) | <0.001 |
| Early term (37-38 weeks) | 2812 | 1.12 (0.97 to 1.30) | 0.11 |
| Full term (39-41 weeks) | 4926 | Reference | — |
| Per additional week (trend) | — | 0.95 (0.93 to 0.98) | 0.001 |
| 20-44 years after delivery | |||
| Preterm (<37 weeks) | 2676 | 1.37 (1.27 to 1.49) | <0.001 |
| Early term (37-38 weeks) | 5571 | 1.08 (1.02 to 1.14) | 0.01 |
| Full term (39-41 weeks) | 11 765 | Reference | — |
| Per additional week (trend) | — | 0.96 (0.95 to 0.97) | <0.001 |
*
Adjusted for shared familial (genetic and environmental) factors, and also for maternal age, year of delivery, parity, education, employment, income, body mass index, smoking, pre-eclampsia, other hypertensive disorders, diabetes, asthma, rheumatoid arthritis, and depression.