Smoking Pregnant Women Risk Giving Birth to Children with Wheezing, Asthma

Smoking during pregnancy is injurious to the child's health. A team of Swedish researchers found exposure to tobacco in the womb escalating the risk of wheezing and asthma in preschool children.

For trouble-free pregnancy, women are often asked to avoid smoking. According to a CDC report, about 14 percent of women in the United States continue smoking even after getting pregnant.

"Epidemiological evidence suggests that exposure to maternal smoking during fetal and early life increases the risk of childhood wheezing and asthma, but earlier studies were not able to differentiate the effects of prenatal and postnatal exposure," lead author Åsa Neuman, from the Institute of Environmental Medicine at the Karolinska Institutet in Stockholm, Sweden,said in a statement.

Neuman and colleagues looked at data from eight studies that included more than 21,000 children. Among them 735 were children exposed to smoking while in the mother's womb. Parents filled questionnaires regarding their smoking habit after conceiving, the child, and health problems like asthma and wheeze problems of their children.

Apart from maternal smoking, other factors like sex, parental education, parental asthma, birth weight and siblings were also analyzed.  However, only maternal smoking was found leading to a higher risk of wheeze and asthma between four and six years.  The risk was found particularly high when the mother smoked during the first trimester of pregnancy than by the end or third trimester or after birth.

"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 Neuman.

"These children were at increased risk for wheeze and asthma at preschool age. Furthermore, the likelihood of developing wheeze and asthma increased in a significant dose-response pattern in relation to maternal cigarette consumption during the first trimester," Neuman added.

Citing the risks associated with women who smoke, investigators urged the young generation to abstain from smoking before planning pregnancy.

"Teens and young women should be encouraged to quit smoking before getting pregnant," Neuman said.

The findings of the study have been published in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

According CDC the following are some of the risks of women smoking before or after pregnancy:

Smoking brings down the chances to get pregnant

Smoking after conceiving the baby increases the risk of miscarriage

Smoking poses problems for placenta like separating from the uterus too early causing bleeding

Smoking before and after birth is one of the important factors leading to Sudden Infant Death Syndrome (SIDS)

Increase the chances to have babies with birth defects, like cleft lip or cleft palate.

Smoking during pregnancy escalates the risk associated with preterm birth.