MONDAY, March 8, 2004 (HealthDayNews) -- Pregnant women prescribed inhaled steroids to control their asthma don't have to worry that the medications will limit their baby's growth in the womb, a new study says.
While pregnant women with asthma often are anxious about continuing to use their medication, the new research in the March issue of the Journal of Allergy and Clinical Immunology found the inhaled steroids did not lead to smaller-than-average babies in the nearly 400 women studied.
"None of our data points to adverse effects on intrauterine growth," says study author Dr. Michael Schatz, chief of the allergy department at Kaiser Permanente in San Diego.
The topic is important because up to 8 percent of pregnant women now have asthma, Schatz says. Going off the medications during pregnancy could result in abnormally low levels of oxygen in the mother-to-be, and that lack of oxygen could actually hurt the fetus, he adds.
Schatz's group evaluated 396 pregnant women from 99 different allergists' practices in 35 states, noting the type of medication each was taking, the dose, and then their babies' birth weights.
They found the incidence of infants with low birth weight, early births and birth defects was not greater than what is statistically expected in the general population, regardless of the dose used.
In the study, 7.1 percent of the babies were born at a low birth weight, below the 10 percent expected in the general population.
Schatz's team defined low birth weight as those babies who were in the less-than-10th percentile of weight for their age, compared to other infants the same gestational age.
Babies who are low birth weight are at increased risk for other health problems, Schatz says, including early death while still a newborn.
Previous studies evaluating asthma medications' effects on birth weight have produced mixed findings. And some studies have found pregnant women with asthma have an increased risk of giving birth early and of having infants with a low birth weight, compared to women without asthma.
Schatz's study looked at five inhaled steroids -- beclomethasone, budesonide, flunisolide, fluticasone and triamcinolone.
Other experts endorse the new study.
"This study should, in fact, ease the worry of pregnant women," says Dr. Sheldon Spector, a clinical professor of medicine at UCLA's David Geffen School of Medicine. He was one of the 99 physicians who referred patients for the study.
The timing of the study is excellent, Spector adds, because inhaled steroids such as those evaluated in the study are now the "mainstay" therapy for persistent asthma.
It's also reassuring, Spector says, that a variety of inhaled steroids were evaluated, and no association was found between any of them and low birth weight babies.
Dr. Frank Virant, a clinical professor of pediatrics at the University of Washington, says, "I'd view this as a relatively positive study."
He advises pregnant women to choose budesonide and fluticasone because they are metabolized more rapidly than some of the other medications, so overall exposure is lower.
Schatz advises pregnant women with asthma to work with their allergy and asthma specialists and follow their advice about whether they need to take inhaled steroid medications.
More information
To learn more about asthma treatment during pregnancy, visit the American Academy of Allergy Asthma & Immunology. For more on asthma, see the American Lung Association.
