PMC

Sample description Unrelated: ^ano birth weight data alone, n = 2; ^bno smoking data alone, n = 5; ^cincomplete attention-deficit/hyperactivity disorder (ADHD) measure alone, n = 9. Related: ^dno birth weight data alone, n = 10; ^eno smoking data alone, n = 14; ^fno ADHD measure alone, n = 25. No prenatal data available was due either to mothers not completing questionnaire or to not giving consent to obtain birth records. Incomplete ADHD measure was due either to mothers not completing questionnaire or to missing some items on the measure.