Pregnant smokers can seriously harm babies' lungs - study

Smoking during pregnancy can stunt the normal development of a foetus's lungs, causing long-term, permanent damage measurable much later in life, according to new research from the University of Southern California School of Medicine.

A study involving 3,357 children aged from nine to 16 whose mothers smoked during pregnancy showed that lung performance was reduced by between 3 per cent and 6.2 per cent in various lung-capacity tests. The damage was also apparently permanent and would not improve over time, stated the chairman of Action on Smoking and Health (ASH) Ireland, Dr Fenton Howell.

"What it is telling us is that children, before they are born, are being damaged on a long-term basis," he said yesterday. He was commenting on the study, published this week in the current edition of Thorax, a medical journal.

"If you have reduced function you can't perform as well as your peers," Dr Howell said. "There is no sign of catching up after they are born. That is a real problem."

The study looked at maternal smoking but also childhood exposure to environmental tobacco smoke. It found that when the damage caused by the in utero exposure was factored out, the lung function change due to environmental smoke was not statistically significant. Measurements were taken of children's "peak expiratory flow rate" and other lung-capacity measures.

The reduction in capacity varied depending on the test in question, but reductions ranged from 3 per cent to 6.2 per cent.

The results caused the authors to conclude: "In utero exposure to maternal smoking is independently associated with decreased lung function in children of school age, especially for small airway flows."

The report was not about blaming women for smoking during pregnancy, Dr Howell said. But smokers needed to be aware of all the risks when considering whether to continue smoking.

Dr Howell called for more Government financial support for smoking cessation programmes, saying it would be an investment in public health.

"We have got to start looking seriously at support, like nicotine replacement therapy."

It would represent the "most cost-effective" approach possible given the high cost of care for people with smoking-related illnesses.

"Our findings have clinical and public health significance," the authors write in their report. "The long-term effects of in utero exposure on the growing lungs of children are of particular concern."

The changes in small airway flows within the lung could reflect "more extensive underlying pathological and functional alterations" greater than those seen in the measurements.