Pregnant women who are treated with a common asthma drug are more likely to have premature or underweight babies than if they hadn't been treated regularly with the drug, a San Diego physician has found.
The oral medication, theophylline, causes three to five times more such problems than occur in women who had their asthma controlled in other ways, said Dr. Michael Schatz of Kaiser Permanente in San Diego.
Furthermore, the use of an alternative to regular theophylline--drugs called inhaled bronchodilators--avoids the problems, he said.
Schatz will report the preliminary results of his 6-year study today at the annual meeting of the American Academy of Allergy and Immunology in Anaheim.
"It's absolute news to let people know that they shouldn't use theophylline during pregnancy, because it's been around for years," Schatz said in an interview Monday.
Funded by the National Institutes of Health, the study compared 360 asthmatic women to 295 non-asthmatics. It found that 8.8% of the women who received more than 200 mg of theophylline daily gave birth prematurely or had babies under 5 1/2 pounds. That compared with about 3% of the control group.
But, among asthmatics who had their asthma treated with the inhaled bronchodilators or therapies other than regular theophylline, only 3.5% had such problems. (Some of the women did receive theophylline occasionally, but not regularly, Schatz said.)
Asthma is a widespread problem involving narrowing of the airways, which keeps the victim from receiving as much oxygen as needed. During pregnancy, there is concern that the fetus will not receive sufficient oxygen for proper development if the mother is asthmatic.
Schatz, who an academy spokeswoman said is nationally regarded as an expert in the field, said he believed that the percentages of problems his statistical analysis uncovered were less significant than the overall conclusion: that inhaled bronchodilators are preferable to theophylline in pregnant women.
"Since there are a number of patients where you could choose to use one over the other, that probably means you should use the inhaled bronchodilators," he said.
In addition, Schatz noted, the data clearly showed that leaving the women's asthma untreated during pregnancy was not a good alternative. The study found that women who scored the poorest in breathing tests were more likely to have babies who had not gained enough weight in utero.
Schatz said the study is continuing with NIH funding of about $60,000 annually.