Maternal smoking during pregnancy and behavioural characteristics in 2 - 4-month-old infants.

The study aimed to assess potential relationship between maternal smoking during pregnancy and behavioural characteristics in 2 - 4-month-old infants. It covered period from 1999 to 2000 and comprised 250 randomly selected, apparently healthy singleton born infants from community setting (129 boys, 121 girls). The mothers were asked to complete the questionnaires addressing infant, maternal, demographic major characteristics with particular emphasis on maternal smoking during pregnancy. To objectively assess behavioural peculiarities of the infants, the mothers were requested to complete the Early Infancy Temperament Questionnaire. Of 250 mothers, 64. women (25.6 %) smoked during pregnancy. The infants of smoking mothers were more often born low birth weight and were also lighter at study; more frequently they were born at earlier gestational age, had lower Apgar score at 5 th minute, were less frequently breast fed at birth and at the time of study. Mothers who smoked during pregnancy were younger, had lower educational level, and less frequently were married. The infants born to smoking mothers had more frequent fussy periods occurring at about the same time of the day, protesting behaviour at face washing and washing in bath, indifferent attitude to the mother when held by new person, extreme reactions (either indifference or much feeling) during diapering and bowel movement, less attention to the parents during parent-infant play activity, and more sensitivity to the wet diaper. They were also characterised by more intensive reactions (displayed more amount of energy regardless of positive or negative behaviour) compared with the babies from the non-smoking group. This association remained after adjustment has been made for major potential confounders, and had a significant "dose-response" effect. Maternal smoking during pregnancy may serve as a risk factor for infant's behavioural deviations.