Table 1. Numbers of mothers, fathers, and children who completed each survey item in the JECS Sub-Cohort Study.
| 1st
trimester |
2nd/3rd
trimester |
Birth | |
|
| |||
| n | n | n | |
| Mother (4,986 pregnancies) | |||
| Questionnaire and interview about drug use | 4,986 | 4,986 | |
| Medical record transcription | 4,986 | 4,986 | |
| Blood | 4,686 | 4,958 | 4,986 |
| Urine | 4,656 | 4,950 | |
| Hair | Xa | ||
| Father (2,696 their partner’s pregnancies) | |||
| Questionnaireb | 2,672 | ||
| Bloodb | 2,652 | ||
| Child (n = 5,017) | |||
| Medical record transcription | 5,017 | ||
| Cord blood | 4,573 | ||
aWe have not yet fixed the data.
bBetween the mother’s early pregnancy and 1 month after delivery, we distributed a questionnaire to fathers, and collected blood from them.