. 2018 Feb 5;28(2):99–104. doi: 10.2188/jea.JE20170018

Table 1. The response rates of the mothers, fathers, and children for each survey item.

	1^st trimester		2^nd/3^rd trimester		Birth

	n	%	n	%	n	%
Mother (100,778 pregnancies)
Questionnaire and interview about drug use	99,300	98.5	97,969	97.2
Medical record transcription	100,611	99.8			100,778	100
Blood	89,434	88.7	96,098	95.4	94,985	94.3
Urine	89,190	88.5	96,341	95.6
Hair					X^a
Father (51,402 with pregnant partners)
Questionnaire	50,014	97.3^b
Blood	49,661	96.6^b
Child (n = 101,779)
Medical record transcription					101,779	100
Cord blood					88,009	87.3^c
Blood					X^a

^aWe have not yet evaluated the data.

^bBetween the mother’s early pregnancy and 1 month after delivery, we distributed a questionnaire to fathers, and collected blood from them.

^cResponse rate of 100,778 pregnancies.