Table 2.
Crude incidence rates (per 100 000 person‐years) and incidence rate ratios (95% confidence interval) of the association between maternal antibiotics use and childhood cancer
| Time of exposure | Exposed | Overall | Leukemias, myeloproliferative diseases, and myelodysplastic diseases | ALL | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cases | Incidence rate | Incidence rate ratio | Cases | Incidence rate | Incidence rate ratio | Cases | Incidence rate | Incidence rate ratio | ||
| Prepregnancy | Yes | 88 | 12 (10‐15) | 0.8 (0.7‐1.1) | 42 | 6 (4‐8) | 1.1 (0.8‐1.6) | 34 | 5 (3‐6) | 1.1 (0.7‐1.7) |
| No | 273 | 14 (12‐16) | 99 | 5 (4‐6) | 80 | 4 (3‐5) | ||||
| Anytime during pregnancy | Yes | 145 | 14 (12‐17) | 1.1 (0.9‐1.4) | 62 | 6 (5‐8) | 1.3 (0.9‐1.8) | 46 | 5 (3‐6) | 1.1 (0.7‐1.6) |
| No | 216 | 13 (11‐15) | 79 | 5 (4‐6) | 68 | 4 (3‐5) | ||||
| First trimester | Yes | 76 | 17 (14‐22) | 1.4 (1.0‐1.8) | 30 | 7 (5‐10) | 1.4 (0.9‐2.1) | 23 | 5 (3‐8) | 1.3 (0.8‐2.1) |
| No | 285 | 13 (11‐14) | 111 | 5 (4‐6) | 91 | 4 (3‐5) | ||||
| Second trimester | Yes | 60 | 12 (9‐15) | 0.8 (0.6‐1.1) | 32 | 6 (4‐9) | 1.2 (0.8‐1.9) | 22 | 4 (3‐7) | 1.0 (0.6‐1.6) |
| No | 301 | 14 (12‐16) | 109 | 5 (4‐6) | 92 | 4 (3‐5) | ||||
| Third trimester | Yes | 61 | 14 (11‐19) | 1.1 (0.8‐1.4) | 26 | 6 (4‐9) | 1.2 (0.8‐1.9) | 19 | 5 (3‐7) | 1.1 (0.6‐1.8) |
| No | 300 | 13 (12‐15) | 115 | 5 (4‐6) | 95 | 4 (3‐5) | ||||
Abbreviation: ALL, acute lymphocytic leukemia.