Table 4.
Association of preterm birth and smoking with maternal myocardial infarction (n = 720)
| Univariate | Multivariate 1 | Multivariate 2 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| HR | 95 % CI | HR | 95 % CI | HR | 95 % CI | ||||
| Term birth | Ref | Ref | Ref | ||||||
| Any preterm birth | 2.26 | 1.82 | 2.80 | 1.84 | 1.47 | 2.31 | 1.65 | 1.32 | 2.07 |
| Preterm birth by severity | |||||||||
| Late preterm birth | 2.09 | 1.59 | 2.77 | 1.80 | 1.36 | 2.38 | 1.63 | 1.23 | 2.15 |
| Moderately preterm birth | 2.61 | 1.49 | 3.80 | 1.98 | 1.24 | 3.18 | 1.73 | 1.08 | 2.78 |
| Extremely preterm birth | 2.38 | 1.73 | 3.92 | 1.85 | 1.17 | 2.94 | 1.66 | 1.05 | 2.62 |
| Preterm birth by onset | |||||||||
| Spontaneous preterm birth | 2.02 | 1.55 | 2.63 | 1.83 | 1.42 | 2.42 | 1.62 | 1.24 | 2.12 |
| Indicated preterm birth | 2.80 | 2.00 | 3.92 | 1.85 | 1.28 | 2.63 | 1.71 | 1.19 | 2.45 |
| Preterm birth by number | |||||||||
| 1 preterm birth | 2.10 | 1.67 | 2.64 | 1.76 | 1.39 | 2.24 | 1.59 | 1.25 | 2.01 |
| ≥2 preterm births | 4.32 | 2.49 | 7.48 | 2.75 | 1.56 | 4.84 | 2.36 | 1.34 | 4.16 |
| Smokinga | |||||||||
| Never smoking during pregnancy | Ref | Ref | |||||||
| Smoking before last pregnancy | 2.45 | 1.71 | 3.52 | 1.78 | 1.23 | 2.58 | |||
| Smoking during last pregnancy | 3.48 | 3.00 | 4.05 | 3.04 | 2.58 | 3.57 | |||
Multivariate 1: Preterm birth adjusted for maternal age at delivery, country of birth, socioeconomic status, number of births, SGA, pregestational and gestational diabetes
Multivariate 2: Variables in Multivariate 1 + maternal smoking during pregnancy
a: Multivariate 2 adjusted for any preterm birth