Smoking during pregnancy ups kids asthma in preschool

A new study has revealed that children whose mothers tend to smoke during pregnancy are more likely to suffer wheeze and asthma in preschool period.

The research, conducted in Karolinska Institute in Sweden, showed how exposure to maternal smoking during fetal and early life increases the risk of childhood wheezing and asthma even among those kids who were not exposed to smoking late in pregnancy or after birth.

"Our study, a large pooled analysis of eight birth cohorts with data on more than 21,000 children, included 735 children who were exposed to maternal smoking only during pregnancy," said Asa Neuman, MD, who is leading author of the Institute of Environmental Medicine at the Stockholm-based institute.

Earlier studies did not demonstrate the different effects of prenatal and postnatal exposure in children, while the recent study makes it clear, Neuman added.

The researchers analyzed the children through considering exposure information and studying symptoms of wheeze and asthma derived from parental questionnaires.

Wheeze is a continuous whistling sound during breathing caused by a narrowing of part of the respiratory tract.

They concluded that children whose mothers smoked while pregnant are 65 percent more likely to develop asthma.

The study also indicated that maternal smoking even during the first three months of pregnancy is associated with increased risks of wheeze and asthma in later years in kids, particularly when they reach preschool age.

"These results indicate that the harmful effects of maternal smoking on the fetal respiratory system begin early in pregnancy, perhaps before the women is even aware that she is pregnant," said Dr. Neuman.