Exposure to smoke in the womb may lead to psychiatric problems, study shows

It's well known that smoking while pregnant isn't good for the baby, but new research shows it could also lead to psychological problems for that baby later in life.
Smoking during pregnancy can increase the need for medication in childhood and young adulthood, according to a study released Tuesday in Vancouver at the Pediatric Academic Societies annual meeting at the Vancouver Convention Centre.
Researchers found that adolescents who had been exposed to prenatal smoking were at increased risk for use of all psychiatric drugs, particularly those used to treat depression, attention-deficit/hyperactivity disorder (ADHD) and addiction, compared to non-exposed youths.
"Recent studies show that maternal smoking during pregnancy may interfere with brain development of the growing fetus," said Mikael Ekblad, 23, lead author of the study and a pediatric researcher at Turku University Hospital in Finland. "By avoiding smoking during pregnancy, all the later psychiatric problems caused by smoking exposure could be prevented."
Results of Ekblad's study show 12.3 per cent of the young adults studied had used psychiatric drugs. Of those, 19.2 per cent had been exposed to prenatal smoking.
"Smoking during pregnancy is still quite common, even though the knowledge of its harmful effects has risen in recent years," Ekblad said.
Young adults whose mothers smoked more than 10 cigarettes a day had the highest rate of psychiatric medication use at 16.9 per cent. The rate among youths whose mothers smoked fewer than 10 a day was 14.7 per cent, and among unexposed youths it was 11.7 per cent.
"There are animal studies that show that nicotine exposure interferes with brain development, in particular the differentiation of cells," Ekblad said, adding that prenatal exposure to smoke is only one reason for depression.
Ekblad said another study he co-authored made the link between smoking and smaller frontal lobes and cerebellums in newborns.
"These are the important regions for normal cognitive development, so we think that might be the mechanism," he said.
According to Physicians for a Smoke-Free Canada, in 2005, approximately one in eight women who gave birth in the past five years reported that they had smoked either daily or occasionally during their last pregnancy. Not all women quit smoking when they discover they are pregnant. A Health Canada report from 2001 found that 58 per cent of the women who smoked at the time of the survey reported that they had smoked during their most recent pregnancy.
Ekblad's study was done using information from the Finnish Medical Birth Register for all children born in Finland from 1987 to 1989. The researchers analyzed records on mothers' psychiatric in-patient care from 1969-1989 and children's use of psychiatric drugs.
The risk for medication use was similar in males and females, and the study was adjusted for risk factors such as maternal age, birth weight and the mother's previous in-patient care for mental disorders.
Exposure to prenatal smoking can also cause an increased risk for respiratory disease, ear infections and asthma when the baby reaches childhood, according to the Pediatric Academic Societies.