A longitudinal study on the effects of maternal smoking and secondhand smoke exposure during pregnancy on neonatal neurobehavior

Maternal smoking during pregnancy is one of the most modifiable causes of morbidity and mortality for both pregnant women and their fetuses. The long-term effects of prenatal exposure to smoke on child behavior and development have been the subject of more extensive research than have the short-term effects. Therefore, the aim of this work is to examine the effects of smoke exposure during pregnancy on neonatal behavior, including in our study a group of mothers exposed to secondhand smoke. The behavior of 282 healthy full-term newborns was assessed using the Neonatal Behavior Assessment Scale (NBAS) at 48-72 h of life. Sixty-two mothers smoked during pregnancy (no mother smoked more than 15 cig/day) and 17 were exposed to secondhand smoke. After adjusting for socio-demographic and obstetric factors, both newborns whose mothers smoked and those whose mothers were exposed to secondhand smoke showed significantly lower scores in the habituation cluster than non-smoking mothers. Exposure to secondhand smoke was also related to lower motor system cluster scores as well as some supplementary items and the newborns of smoking mothers showed significantly lower scores in the state regulation cluster and in some items of the state organization cluster than the newborns of non-smoking mothers. We conclude that active and passive smoking during pregnancy affects several aspects of neurobehavioral development, regardless of socio-demographic, obstetric and pediatric factors.