Taking Asthma Drug During Pregnancy Associated With Greater Autism Risk

Prescription drug use may elevate potential autism spectrum disorder risk factor.

Women who take a specific anti-asthma drug during pregnancy face a greater risk of having their child develop autism, a recent study indicates.

Patients with asthma are commonly administered B-2-andrenergic receptor (B2AR) agonist drugs, including salmetereol and formoterol, to help alleviate and relax constriction in the bronchial passages in the lungs.

However, the results of a study published in Pediatrics showed that B2AR can cross the placenta and reach the fetus. This could potentially have an effect on the developing neurons.

"Since the teratogenic (an agent which could cause development issues in a fetus) potential of most drugs with respect to neurodevelopmental outcomes is generally understudied, I would hope my research would encourage more researchers to explore prescription drug use as a potential autism spectrum disorder risk factor," said lead author Nicole Gidaya, PhD.

The study examined birth records from January 1, 1996 to December 31, 2006, of pregnant mothers in Denmark who took B2AR agonist drugs.

There were 5200 children diagnosed with autism who were part of the case group, and 52,000 children who were not diagnosed in the control group. Mothers who had filled their prescriptions from 90 days before the conception date through to the birth date were considered to have been exposed to the drug.

The results of the study showed that of the mothers who had taken the B2AR agonist drugs during pregnancy, 3.7% of their children were diagnosed with autism, while 2.9% of children who were born from mothers who took the drug did not have autism.

"This study adds to a body of recent research suggesting that medications used for certain common health conditions like asthma, when taken in pregnancy, may influence a newborn's neurodevelopment," said co-author Craig Newschaffer, PhD.

Although the study found there are risks for children whose mothers had taken the drug during pregnancy, it could be just as harmful if the B2AR agonists drugs were not taken. According to the study, uncontrolled asthma during pregnancy is associated with poor birth outcomes.

"A challenge here is that the effects of the underlying health conditions, themselves, can also influence developmental outcomes," Newschaffer said. "Newly pregnant women taking medication for asthma or other conditions need to work closely with their health care provider to weigh the benefits of continuing medication use against possible risks."

Prior to the current study, there has only been 1 other smaller scaled study on B2AR prenatal exposure. Although it has some important data, further research needs to be done, the study concluded. According to the research team, out of the entire study population --- about 628,000 children, less than 1% of autism diagnoses were attributed to the B2AR agonist drug exposure.