The effect of trimester specific and pregnancy average total trihalomethane (TTHM) exposure on birth weight among term births
| Δ Birth weight (g) | ||||
|---|---|---|---|---|
| TTHM (μg/l) | First trimester | Second trimester | Third trimester | Pregnancy average |
| *Regression coefficients adjusted for gestational age, 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 | ||||
| 0–60 | Reference | Reference | Reference | Reference |
| >60–80 | −3 (−18 to 11) | −7 (−22 to 8) | −3 (−17 to 11) | −5 (−18 to 7) |
| >80 | −21 (−36 to −6) | −29 (−43 to −15) | −22 (−36 to −8) | −47 (−62 to −31) |
| Per each 20 μg/l | −1.6 (−3.8 to 0.5) | −2.9 (−5.3 to −0.6) | −3.3 (−6.0 to −0.6) | −3.4 (−6.1 to −0.6) |
| p value | 0.14 | 0.01 | 0.02 | 0.02 |
| Adjusted* | ||||
| 0–60 | Reference | Reference | Reference | Reference |
| >60–80 | −4 (−18 to 9) | −5 (−19 to 9) | −9 (−22 to 4) | −1 (−12 to 11) |
| >80 | −17 (−31 to −3) | −23 (−36 to −10) | −11 (−24 to 2) | −32 (−47 to −18) |
| Per each 20 μg/l | −1.8 (−3.8 to 0.2) | −2.6 (−4.8 to −0.4) | −1.8 (−4.4 to 0.8) | −2.8 (−5.5 to −0.2) |
| p value | 0.08 | 0.02 | 0.17 | 0.03 |