Table 2. Odds ratios (OR) and 95% confidence intervals (CI) for association between opium and tobacco use during pregnancy and risk of preterm delivery.
| Pregnancies N |
Events | Crude OR (95% CI) |
Model A1 OR (95% CI) |
Model B2 OR (95% CI) |
||
|---|---|---|---|---|---|---|
| N | (%) | |||||
| Opium | ||||||
| Unexposed | 905 | 55 | (6.1) | Reference | ||
| Exposed | 887 | 89 | (10.0) | 1.73 (1.22–2.45) | 1.74 (1.21–2.45) | 1.69 (1.16–2.44) |
| Tobacco and opium | ||||||
| Unexposed | 905 | 55 | (6.1) | Reference | ||
| Exposed to opium only | 677 | 61 | (9.0) | 1.53 (1.05–2.23) | 1.56 (1.05–2.32) | 1.51 (1.01–2.24) |
| Exposed to tobacco and opium | 210 | 28 | (13.3) | 2.38 (1.47–3.85) | 2.40 (1.43–4.04) | 2.37 (1.40–3.99) |
1Adjusted for: maternal age, height, BMI, parity, husband’s occupation, infant sex, delivery method, and residential place.
2Adjusted for all covariates which are included in Model A plus hypertension during the pregnancy and small for gestational age.