Table 2
Crude and adjusted relative risks (RRs) of congenital anomalies related to exposure to bromodichloromethane (BDCM) and chloroform during pregnancy
| Defects and anomalies |
Cases (births) n2-150 |
Rate/1000 |
Crude RR (95% CI) |
Adjusted RR (95% CI) |
| Neural tube defects: | ||||
| BDCM (μg/l): | ||||
| <5 | 35 (26636) | 1.3 | 1.0 | 1.02-151 |
| 5–9 | 27 (13837) | 2.0 | 1.5 (0.9 to 2.5) | 1.4 (0.8 to 2.3)2-151 |
| 10–19 | 5 (5638) | 0.9 | 0.7 (0.3 to 1.7) | 0.6 (0.2 to 1.5)2-151 |
| ⩾20 | 10 (2734) | 3.7 | 2.8 (1.4 to 5.6) | 2.5 (1.2 to 5.1)2-151 |
| Chloroform(μg/l): | ||||
| <50 | 33 (18964) | 1.7 | 1.0 | 1.02-151 |
| 50–74 | 19 (16323) | 1.2 | 0.7 (0.4 to 1.2) | 0.7 (0.4 to 1.2)2-151 |
| 75–99 | 8 (6685) | 1.2 | 0.7 (0.3 to 1.5) | 0.7 (0.3 to 1.5)2-151 |
| ⩾100 | 17 (6873) | 2.5 | 1.4 (0.8 to 2.6) | 1.2 (0.7 to 2.3)2-151 |
| Cardiovascular anomalies: | ||||
| BDCM (μg/l): | ||||
| <5 | 258 (26977) | 9.6 | 1.0 | 1.02-151 |
| 5–9 | 125 (13653) | 9.2 | 1.0 (0.8 to 1.2) | 1.0 (0.8 to 1.2)2-151 |
| 10–19 | 39 (5546) | 7.0 | 0.7 (0.5 to 1.0) | 0.7 (0.5 to 1.0)2-151 |
| ⩾20 | 8 (2669) | 3.0 | 0.3 (0.2 to 0.6) | 0.3 (0.2 to 0.7)2-151 |
| Chloroform (μg/l): | ||||
| <50 | 170 (19057) | 8.9 | 1.0 | 1.02-151 |
| 50–74 | 153 (16350) | 9.4 | 1.0 (0.8 to 1.3) | 1.0 (0.8 to 1.3)2-151 |
| 75–99 | 60 (6550) | 9.2 | 1.0 (0.8 to 1.4) | 1.0 (0.8 to 1.4)2-151 |
| ⩾100 | 47 (6888) | 6.8 | 0.8 (0.6 to 1.1) | 0.7 (0.5 to 1.0)2-151 |
| Cleft defects: | ||||
| BDCM (μg/l): | ||||
| <5 | 50 (27426) | 1.8 | 1.0 | 1.02-152 |
| 5–9 | 17 (13972) | 1.2 | 0.7 (0.4 to 1.2) | 0.7 (0.4 to 1.2)2-152 |
| 10–19 | 12 (5723) | 2.1 | 1.2 (0.6 to 2.2) | 1.1 (0.6 to 2.1)2-152 |
| ⩾20 | 3 (2721) | 1.1 | 0.6 (0.2 to 1.9) | 0.6 (0.2 to 1.9)2-152 |
| Chloroform (μg/l): | ||||
| <50 | 28 (19351) | 1.4 | 1.0 | 1.02-152 |
| 50–74 | 29 (16597) | 1.7 | 1.2 (0.7 to 2.0) | 1.2 (0.7 to 2.0)2-152 |
| 75–99 | 9 (6696) | 1.3 | 0.9 (0.4 to 2.0) | 0.9 (0.4 to 2.0)2-152 |
| ⩾100 | 16 (7198) | 2.2 | 1.5 (0.8 to 2.8) | 1.5 (0.8 to 2.8)2-152 |
| Chromosomal abnormalities: | ||||
| BDCM (μg/l): | ||||
| <5 | 54 (26214) | 2.1 | 1.0 | 1.02-151 |
| 5–9 | 29 (14565) | 2.0 | 1.0 (0.6 to 1.5) | 1.0 (0.6 to 1.5)2-151 |
| 10–19 | 8 (5304) | 1.5 | 0.7 (0.3 to 1.5) | 0.7 (0.4 to 1.6)2-151 |
| ⩾20 | 5 (2762) | 1.8 | 0.9 (0.4 to 2.2) | 0.9 (0.4 to 2.3)2-151 |
| Chloroform (μg/l): | ||||
| <50 | 30 (19416) | 1.5 | 1.0 | 1.02-151 |
| 50–74 | 33 (16086) | 2.1 | 1.3 (0.8 to 2.2) | 1.3 (0.8 to 2.2)2-151 |
| 75–99 | 19 (6721) | 2.8 | 1.8 (1.0 to 3.3) | 1.9 (1.1 to 3.3)2-151 |
| ⩾100 | 14 (6622) | 2.1 | 1.4 (0.7 to 2.6) | 1.4 (0.8 to 2.8)2-151 |
