Table 4.
Preterm 20- < 37 weeks | ||||
Smoking Status | Crude OR | 95% CI | Adjusted ORa | 95% CI |
No trimester smokers | 0.56 | 0.53, 0.59* | 0.60 | 0.57, 0.63* |
1st trimester only, low | 0.65 | 0.61, 0.70* | 0.66 | 0.62, 0.71* |
1st trimester only, high | 0.64 | 0.57, 0.71* | 0.65 | 0.58, 0.73* |
1st & 2nd trimesters, low (ref.) | 1 | 1 | 1 | 1 |
1st & 2nd trimesters,high | 1.22 | 1.09, 1.37* | 1.23 | 1.09, 1.38* |
2nd & 3rd trimesters, low | 0.64 | 0.58, 0.71* | 0.63 | 0.57, 0.70* |
2nd & 3rd trimesters, high | 0.70 | 0.53, 0.92* | 0.68 | 0.51, 0.90* |
All 3 trimesters, low | 0.79 | 0.75, 0.84* | 0.79 | 0.75, 0.84* |
All 3 trimesters, high | 0.86 | 0.81, 0.91* | 0.88 | 0.83, 0.94* |
Preterm 28- < 37 weeks | ||||
Smoking Status | Crude OR | 95% CI | Adjusted ORa | 95% CI |
No trimester smokers | 0.66 | 0.62, 0.70* | 0.70 | 0.66, 0.75* |
1st trimester only, low | 0.75 | 0.70, 0.81* | 0.76 | 0.71, 0.82* |
1st trimester only, high | 0.72 | 0.64, 0.82* | 0.73 | 0.65, 0.83* |
1st & 2nd trimesters, low (ref.) | 1 | 1 | 1 | 1 |
1st & 2nd trimesters, high | 1.22 | 1.07, 1.38* | 1.22 | 1.08, 1.39* |
2nd & 3rd trimesters, low | 0.77 | 0.69, 0.86* | 0.76 | 0.68, 0.85* |
2nd & 3rd trimesters, high | 0.82 | 0.61, 1.09 | 0.80 | 0.59, 1.07 |
All 3 trimesters, low | 0.95 | 0.89, 1.01 | 0.95 | 0.89, 1.01 |
All 3 trimesters, high | 1.04 | 0.98, 1.12 | 1.07 | 0.99, 1.14 |
aAnalyses were adjusted for: maternal race/ethnicity, age, education, and marital status; low intensity: 1–19 cigarettes/day; high intensity: ≥ 20 cigarettes/day; *p < 0.05; CI-confidence interval