Smoking in pregnancy and children's mental and motor development at age 1 and 5 years

We used data from a Scandinavian prospective multicenter study to investiga te if smoking in pregnancy may have an adverse effect on the child's mental and motor abilities. Eligible for enrolment were para 1 and 2 women with a singleton pregnancy, who resided in one of the study areas and could be re gistered before the 20th gestational week. Women were classified as 'smoker s' or 'non-smokers' at study start. At 13 months, 376 children (124 childre n of smokers) were evaluated with the Bayley Scales of Infant Development. At this age, children of smokers and non-smokers performed equally well. At 5 years, 369 children (132 children of smokers) were tested with the Wechs ler Preschool and Primary Scales of intelligence Revised (WPPSI-R), and 362 children with the Peabody Developmental Motor Scales (PDMS). Children of s mokers had an increased risk of getting a WPPSI-R score below the median va lue of the population (OR = 2.1, 95% CI: 1.2-3.3), but the risk was reduced when we adjusted for maternal education (OR = 1.6, 95% CI: 0.9-3.7). Child ren of smokers had an increased risk of getting a test score below the medi an population Value on the subscale 'balance' from PDMS (OR = 1.8, 95% CI: 1.2-2.8). Thus, we found that smoking in pregnancy was associated with a sm all, but demonstrable adverse effect on the child's balance at 5 years, whe reas the negative effect on cognitive function did not reach statistical si gnificance, when we adjusted for the mother's level of education. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.