Pregnancy asthma flare-ups tied to birth defects
NEW YORK (Reuters Health) - Women who experience asthma flare-ups during the first trimester of pregnancy are at increased risk for having a baby with a birth defect, according to a report in the Journal of Allergy and Clinical Immunology.
A first-trimester flare-up increased the odds of a malformation by 48 percent, note Dr. Lucie Blais and Amelie Forget, from Universite de Montreal and Hopital du Sacre-Coeur de Montreal. For major malformations, the risk increased by 32 percent.
"This study adds evidence to the necessity of keeping asthma under control during pregnancy to avoid exacerbations," the investigators write.
Several studies have looked at the link between asthma flare-ups and the risk of birth defects, the authors point out. However, most of the studies were small and many of them compared asthmatic women who had flare-ups to non-asthmatic women, so the impact of the flare-up itself was unclear.
Through the use of three Canadian databases, the researchers were able to assess the occurrence of and risk factors for birth defects in 4344 pregnancies involving women with asthma.
Asthma flare-ups, which were assessed during the first trimester, were defined as a filling a prescription for steroid pills, an ER visit, or an asthma-related hospitalization.
Overall, 9.2 percent of the babies had one or more defects and 6.0 percent of the infants had a major malformation. Defects of the skeleton and muscles were the most common followed by those involving the heart.
Overall, 12.8 percent of women with a flare-up had a child with birth defects compared with 8.9 percent of women without a flare-up.
"Because recent data are reassuring about the safety of (steroid inhalers) during pregnancy, health professionals should encourage pregnant women to continue their treatment at recommended doses once they know that they are pregnant to control their asthma symptoms, thus avoiding exacerbations and the need for (steroid pills)," the researchers emphasize.
SOURCE: Journal of Allergy and Clinical Immunology, June 2008.