Prevention of intellectual impairment in children of women who smoke cigarettes during pregnancy.

OBJECTIVE

To analyze the influence of a comprehensive program of nurse home visitation on the intellectual functioning of children born to women who smoked cigarettes during pregnancy.

DESIGN

Randomized clinical trial. Treatment 1: sensory and developmental screening at ages 1 and 2 years; treatment 2: screening plus free transportation for prenatal and well-child care; treatment 3: screening, transportation, plus prenatal home visitation; treatment 4: screening, transportation, prenatal home visitation, plus postnatal home visitation through the children's second birthdays.

SETTING

Semi-rural community in Upstate New York.

PARTICIPANTS

400 families in which the mothers registered before the 30th week of pregnancy and had no previous live births. Eighty-five percent of the mothers were either teenagers, unmarried, or poor. Analysis was limited to whites, who constituted 89% of sample.

INTERVENTION

Nurse home visitation during pregnancy (treatments 3 and 4) or during pregnancy and the first 2 years of the child's life (treatment 4). During pregnancy, the nurses helped women improve their health-related behaviors, informal social support, and linkage with needed community services.

MAIN FINDINGS

Children born to women who smoked 10 or more cigarettes per day at registration during pregnancy and who were assigned to treatments 3 and 4 had IQs (averaging across the 3rd and 4th years of life) that were 4.86 (95% CI: 0.47, 9.26) points higher after adjustment for covariates than did children born to women who smoked 10+ cigarettes per day and who were assigned to treatments 1 and 2. The positive influence of the home-visiting program on reducing the harmful effect of smoking appears to be due to prenatal visitation.

CONCLUSION

Comprehensive prenatal home-visitation services can offset the impairment in intellectual functioning associated with substantial maternal smoking during pregnancy.