SAN ANTONIO — Pregnant women with asthma take less asthma medication than do nonpregnant women with asthma, according to a new study that did not measure the effect of the medication reduction.
“Whether they stopped taking their medications because their symptoms improved, or whether they were reluctant to take their medications, we don't know,” lead investigator Ami Degala, M.D., told this newspaper.
Research shows that among women with asthma, about one-third get better during pregnancy. In addition, asthma symptoms worsen in one-third and remain the same in another third. But physicians and pregnant women alike are often conservative with asthma medication during pregnancy to avoid overexposing the fetus, said Dr. Degala, a fellow in allergy and clinical immunology at Henry Ford Hospital in Detroit.
In her study, which was presented as a poster at the annual meeting of the American Academy of Asthma, Allergy, and Immunology, the asthma medication refill habits of 240 women with asthma were observed for a 1-year surveillance period.
After this time, the refill habits of 80 women who became pregnant were compared during the last two trimesters with the refill habits of 160 nonpregnant participants who were assigned matched delivery dates.
Among women who did not take their controller medication during the surveillance period, only 9% started taking the medication when they became pregnant, compared with 22% of the nonpregnant controls during this same period. And 25% of the pregnant women used their rescue medication, compared with 59% of controls.
A similar pattern was seen among women who did take their controller medication during the surveillance period, with only 33% of pregnant women continuing their controller medications, compared with 59% of controls, and 52% of pregnant women continuing their rescue medications, compared with 62% of controls.
Overall, there was a statistically significant difference between pregnant women and controls in the reduction in medication between the surveillance and pregnancy periods. Medication refills were reduced by 43% in pregnant women over this period, while they were reduced by 15% in controls.
Although there is evidence that oral corticosteroids can have adverse effects on the fetus, there is no such evidence for β-agonists, inhaled corticosteroids, or even theophylline, Dr. Degala said.
In contrast, there is evidence of both fetal and maternal risks in undertreating asthma.
“There's a risk of fetal and maternal hypoxia, and studies also show an increased risk of perinatal mortality and low birth weight,” she said.