Univariate | Multivariate 1 | Multivariate 2 | |||||||
---|---|---|---|---|---|---|---|---|---|
HR | 95 % CI | HR | 95 % CI | HR | 95 % CI | ||||
Term birth | Ref | Ref | Ref | ||||||
Any preterm birth | 2.01 | 1.83 | 2.20 | 1.78 | 1.61 | 1.96 | 1.65 | 1.50 | 1.83 |
Preterm birth by severity | |||||||||
Late preterm birth | 1.79 | 1.59 | 2.03 | 1.63 | 1.44 | 1.85 | 1.53 | 1.35 | 1.74 |
Moderately preterm birth | 2.36 | 1.89 | 2.80 | 2.06 | 1.69 | 2.51 | 1.89 | 1.55 | 2.31 |
Extremely preterm birth | 2.30 | 1.97 | 2.82 | 1.98 | 1.63 | 2.42 | 1.83 | 1.50 | 2.23 |
Preterm birth by onset | |||||||||
Spontaneous preterm birth | 1.73 | 1.54 | 1.95 | 1.65 | 1.47 | 1.86 | 1.53 | 1.35 | 1.72 |
Indicated preterm birth | 2.63 | 2.28 | 3.04 | 2.04 | 1.75 | 2.38 | 1.93 | 1.66 | 2.25 |
Preterm birth by number | |||||||||
1 preterm birth | 1.92 | 1.74 | 2.12 | 1.73 | 1.57 | 1.92 | 1.62 | 1.46 | 1.79 |
≥2 preterm births | 3.06 | 2.35 | 3.98 | 2.29 | 1.75 | 2.99 | 2.04 | 1.56 | 2.67 |
Smokinga | |||||||||
Never smoking during pregnancy | Ref | Ref | |||||||
Smoking before last pregnancy | 2.10 | 1.81 | 2.43 | 1.64 | 1.41 | 1.90 | |||
Smoking during last pregnancy | 2.29 | 2.14 | 2.44 | 2.07 | 1.93 | 2.23 |