Risks of exposure to smoking in womb

Infants whose mothers smoked during pregnancy are at increased risk for hospitalisation and death due to both respiratory and non-respiratory infections, a new study says.

Researchers analysed hospitalisation records and death certificates of 50 000 infants born in Washington state between 1987 and 2004. Infants whose mothers smoked during pregnancy were 50% more likely to be hospitalised or to die from a wide number of infectious diseases, compared to babies of mothers who did not smoke.

Immune system weakened

Smoking during pregnancy may weaken an infant's immune system and put them at increased risk for a broad range of infections, according to the authors of the study to be presented Sunday at an American Academy of Paediatrics meeting, in Orlando, Florida. The findings were also published earlier this year in the journal Paediatric Infectious Diseases.

"We've known for a long time that babies born to mothers who smoke during pregnancy are at high risk for serious medical problems relating to low birth weight, premature delivery and poor lung development," lead study author Dr Abigail Halperin said in an AAP news release.

"While respiratory infections have been recognised as a common cause of these sometimes life-threatening illnesses, this study shows that babies exposed to smoke in utero [in the womb] also have increased risk for hospitalisation and death from a much broader range of infections, both respiratory and non-respiratory, than we knew before," she noted.

The researchers also found that when smokers reduced their cigarette smoking or quit during their pregnancy, their infants had a lower risk of infection.

"Counselling pregnant women to reduce their smoking, if they are not able to quit completely, may help reduce infant hospitalisations or death," Halperin said.

Although the study found an association between maternal smoking during pregnancy and infants' risk for hospitalisation and death from infections, it did not establish a cause-and-effect relationship.

More information

The March of Dimes has more about smoking during pregnancy.