Table 1.
Participant Characteristics.
| Total | Fukushima RC | Other 14 RCs | |||||
|---|---|---|---|---|---|---|---|
| n = 101,729 | n = 12,958 | n = 88,771 | |||||
| n | % | n | % | n | % | ||
| Maternal age at delivery | ≤24 | 10174 | 10.0 | 1595 | 12.3 | 8579 | 9.7 |
| 25-34 | 63846 | 62.8 | 8349 | 64.4 | 55497 | 62.5 | |
| ≥35 | 27684 | 27.2 | 3012 | 23.2 | 24672 | 27.8 | |
| No answer | 25 | 0.02 | 2 | 0.02 | 23 | 0.03 | |
| Maternal BMI (kg/m2) before pregnancy | <18.5 | 16419 | 16.1 | 1884 | 14.5 | 14535 | 16.4 |
| 18.5≤-<25.0 | 74104 | 72.8 | 9411 | 72.6 | 64693 | 72.9 | |
| ≥25.0 | 10965 | 10.8 | 1653 | 12.8 | 9312 | 10.5 | |
| No answer | 241 | 0.2 | 10 | 0.1 | 231 | 0.3 | |
| Infertility treatment | No | 94121 | 92.5 | 12262 | 94.6 | 81859 | 92.2 |
| Yes | 7007 | 6.9 | 690 | 5.3 | 6317 | 7.1 | |
| No answer | 601 | 0.6 | 6 | 0.1 | 595 | 0.7 | |
| Multiple pregnancy | No | 99741 | 98.1 | 12707 | 98.1 | 87034 | 98.0 |
| Yes | 1988 | 2.0 | 251 | 1.9 | 1737 | 2.0 | |
| Maternal smoking during pregnancy | No | 94241 | 92.6 | 12270 | 94.7 | 81971 | 92.3 |
| Yes | 4765 | 4.7 | 557 | 4.3 | 4208 | 4.7 | |
| No answer | 2723 | 2.7 | 131 | 1.0 | 2592 | 2.9 | |
| Maternal alcohol consumption during pregnancy | No | 89443 | 87.9 | 11551 | 89.1 | 77892 | 87.7 |
| Yes | 9848 | 9.7 | 1284 | 9.9 | 8564 | 9.7 | |
| No answer | 2438 | 2.4 | 123 | 1.0 | 2315 | 2.6 | |
| Pregnancy complication | No | 84309 | 82.9 | 11698 | 90.3 | 72611 | 81.8 |
| Yes | 15140 | 14.9 | 1138 | 8.8 | 14002 | 15.8 | |
| No answer | 2280 | 2.2 | 122 | 0.9 | 2158 | 2.4 | |
| Maternal infection | No | 98811 | 97.1 | 12740 | 98.3 | 86071 | 97.0 |
| Yes | 2918 | 2.9 | 218 | 1.7 | 2700 | 3.0 | |
| Birth | Live birth | 100054 | 98.4 | 12803 | 98.8 | 87251 | 98.3 |
| Stillbirth | 382 | 0.4 | 70 | 0.5 | 312 | 0.4 | |
| Spontaneous abortion or induced abortion | 1254 | 1.2 | 85 | 0.7 | 1169 | 1.3 | |
| No answer | 39 | 0.04 | 0 | 0.00 | 39 | 0.04 | |
| Sex of infants | Boy | 51711 | 50.8 | 6674 | 51.5 | 45037 | 50.7 |
| Girl | 49033 | 48.2 | 6234 | 48.1 | 42799 | 48.2 | |
| Unknown | 535 | 0.5 | 39 | 0.3 | 496 | 0.6 | |
| No answer | 450 | 0.4 | 11 | 0.1 | 439 | 0.5 | |
Abbreviations: regional center (RC), body mass index (BMI)
Pregnancy complications included hypertension, hyperthyroidism, hypothyroidism, diabetes, autoimmune disease, cardiac disease, renal disease, hepatitis, cerebral infarction, intracerebral hemorrhage, epilepsy, hematological disease, malignant tumor, psychiatric disease, neurological disease, thrombosis, and others.
Maternal infection included toxoplasmosis, syphilis, HBV hepatitis, rubella, cytomegalovirus infection, herpes simplex virus infection.