MONTEREY, CALIF. — Women who take anti-inflammatories for asthma during the first trimester of pregnancy have an elevated risk of giving birth to an infant with anorectal atresia, according to results of a multicenter, case-control study of more than 7,000 women.
Anti-inflammatory use was not associated with any other birth defects, nor was the use of bronchodilators, Shao Lin, Ph.D., and colleagues at the New York State Department of Health reported in a poster presentation at the annual meeting of the Teratology Society.
The multicenter case-control study was part of the National Birth Defects Prevention Study, which collects data from 10 regions in the United States.
The investigators included women exposed to asthma medications at least once during a critical period defined as between 1 month prior to pregnancy and the end of the third pregnancy month. They focused on babies born between 1997 and 2003 with one of seven birth defects: diaphragmatic hernia, esophageal atresia, intestinal atresia, anorectal atresia, neural tube defects, omphalocele, and limb reduction.
In all, the investigators identified 2,248 infants with birth defects born to mothers taking asthma medications. They compared them with 4,986 nonmalformed, live-born infants identified by birth certificates or birth hospitals.
After adjusting for age, body mass index, parity, race/ethnicity, education, alcohol use, smoking, gender, folic acid use, fever, cocaine use, and the use of seven different vasoactive medications, the investigators found no significantly increased risks of birth defects associated with maternal bronchodilator use. Maternal anti-inflammatory use, on the other hand, was associated with a statistically significant 2.6-fold increase in the risk of anorectal atresia. There were no other statistically significant associations between anti-inflammatory use and birth defects.
The investigators acknowledged that their study could not determine whether it was the anti-inflammatories or the asthma itself that was the causal agent. The use of asthma medications during the entire critical period could be an indication of especially severe asthma. They wrote that further studies would be needed to separate the effects of asthma from the effects of asthma treatment.
Dr. Lin disclosed no conflicts of interest associated with the study.