Adjusted ORs and 95% CIs for congenital heart anomalies by tertiles of internal THM exposure during the first trimester of pregnancy
| THM internal dose tertile limits (µg/d) | n | First month OR* (95% CI) | n | Second month OR* (95% CI) | n | Third month OR* (95% CI) | n | First trimester OR* (95% CI) |
|---|---|---|---|---|---|---|---|---|
| TTHM | ||||||||
| 0.031–0.040 | 16 | 1 | 15 | 1 | 18 | 1 | 16 | 1 |
| 0.040–0.356 | 17 | 0.94 (0.47 to 1.88) | 19 | 1.15 (0.58 to 2.28) | 17 | 0.85 (0.43 to 1.67) | 18 | 1.05 (0.53 to 2.07) |
| 0.356–2.448 | 24 | 1.44 (0.76 to 2.74) | 23 | 1.50 (0.78 to 2.91 | 22 | 1.17 (0.62 to 2.12) | 23 | 1.38 (0.72 to 2.64) |
| p† | 0.162 | 0.158 | 0.450 | 0.237 | ||||
| Continuous (1 µg/d) | 1.96 (1.01 to 3.80) | 1.90 (0.98 to 3.70) | 1.72 (0.87 to 3.39) | 1.88 (0.96 to 3.69) | ||||
| Chloroform | ||||||||
| 0.001–0.026 | 17 | 1 | 17 | 1 | 16 | 1 | 16 | 1 |
| 0.026–0.288 | 16 | 0.83 (0.41 to 1.65) | 17 | 0.88 (0.45 to 1.75) | 19 | 1.06 (0.54 to 2.08) | 18 | 1.05 (0.53 to 2.08) |
| 0.288–2.109 | 24 | 1.36 (0.72 to 2.56) | 23 | 1.31 (0.70 to 2.49) | 22 | 1.34 (0.69 to 2.57) | 23 | 1.37 (0.72 to 2.63) |
| p† | 0.225 | 0.283 | 0.279 | 0.245 | ||||
| Continuous (1 µg/d) | 2.07 (0.96 to 4.46) | 2.01 (0.92 to 4.38) | 1.79 (0.80 to 3.99) | 1.97 (0.90 to 4.35) | ||||
| BDCM | ||||||||
| 0.000–0.013 | 11 | 1 | 14 | 1 | 16 | 1 | 12 | 1 |
| 0.013–0.051 | 22 | 1.87 (0.90 to 3.88) | 21 | 1.40 (0.71 to 2.78) | 20 | 1.19 (0.61 to 2.31) | 22 | 1.74 (0.85 to 3.54) |
| 0.051–0.436 | 24 | 2.16 (1.05 to 4.46) | 22 | 1.54 (0.78 to 3.04) | 21 | 1.32 (0.68 to 2.56) | 23 | 1.82 (0.89 to 3.69) |
| p† | 0.024 | 0.144 | 0.309 | 0.070 | ||||
| Continuous (0.1 µg/d) | 1.77 (1.13 to 2.78) | 1.69 (1.09 to 2.62) | 1.59 (1.02 to 2.46) | 1.70 (1.09 to 2.66) | ||||
| DBCM | ||||||||
| 0.000–0.002 | 20 | 1 | 18 | 1 | 17 | 1 | 18 | |
| 0.002–0.006 | 21 | 0.96 (0.52 to 1.79) | 22 | 1.17 (0.62 to 2.20) | 22 | 1.24 (0.65 to 2.36) | 14 | 0.73 (0.36 to 1.48) |
| 0.006–0.093 | 16 | 0.71 (0.37 to 1.39) | 17 | 0.87 (0.45 to 1.71) | 18 | 1.00 (0.51 to 1.97) | 25 | 1.35 (0.73 to 2.51) |
| p† | 0.398 | 0.742 | 1.000 | 0.283 | ||||
| Continuous (0.01 µg/d) | 1.26 (1.01 to 1.58) | 1.24 (1.01 to 1.52) | 1.23 (1.00 to 1.50) | 1.25 (1.01 to 1.54) | ||||
*Adjusted for: age, body mass index, chronic disease, alcohol consumption and fetus number.
†χ2 for linear trend.
BDCM, bromodichloromethane; DBCM, dibromochloromethane; THM, trihalomethane; TTHM, total trihalomethane.