Crude and adjusted odds ratios and 95% CI of preterm delivery for trimester specific and pregnancy average total trihalomethane (TTHM) exposure among all births
| Preterm delivery | ||||
|---|---|---|---|---|
| TTHM (μg/l) | First trimester | Second trimester | Third trimester | Pregnancy average |
| *Odds ratios adjusted for infant gender, adequacy of prenatal care, maternal race, maternal education, maternal smoking, maternal age, parity, median household income, previous infant weighing 4000 g or more, previous preterm delivery, and maternal medical history (diabetes, eclampsia, hydramnios, chronic hypertension, hypertension during pregnancy, incompetent cervix, lung disease, renal disease, and uterine bleeding). | ||||
| Crude OR (95% CI) | ||||
| 0–60 | 1.0 | 1.0 | 1.0 | 1.0 |
| >60–80 | 0.97 (0.86 to 1.10) | 1.03 (0.91 to 1.17) | 1.00 (0.88 to 1.13) | 0.90 (0.80 to 1.01) |
| >80 | 1.00 (0.88 to 1.13) | 0.92 (0.81 to 1.04) | 1.01 (0.89 to 1.14) | 0.93 (0.85 to 1.01) |
| Adjusted OR (95% CI)* | ||||
| 0–60 | 1.0 | 1.0 | 1.0 | 1.0 |
| >60–80 | 0.96 (0.84 to 1.10) | 1.02 (0.89 to 1.16) | 0.99 (0.87 to 1.13) | 1.00 (0.89 to 1.12) |
| >80 | 1.01 (0.88 to 1.16) | 0.90 (0.79 to 1.03) | 0.97 (0.85 to 1.11) | 0.90 (0.77 to 1.04) |