Prenatal smoking exposure is associated with an increased risk of psychiatric morbidity, whereas prenatal exposure to more than 10 cigarettes a day increases the risk of mortality in childhood, adolescence, and young adulthood.

Smoking during pregnancy exposes the foetus to thousands of health-threatening chemicals, restricting foetal body and head growth. Alterations in brain structure and function have been seen in children exposed to prenatal smoking.

Maternal smoking and its trends differed between the Nordic countries. The highest smoking rates during pregnancy were observed among teenagers, single women and women with a low socioeconomic position.