Asthma Drugs in Pregnancy Linked to Slight Risk of Rare Birth Defects

Researchers Unclear Whether Medications or the Severity of the Asthma Led to Rare Defects

Reviewed by Hansa D. Bhargava, MD on January 17, 2012
From the WebMD Archives

Jan. 17, 2012 -- New research provides some reassuring news for many pregnant women who have asthma.

Treating your asthma during pregnancy most likely does not increase your baby’s risk for most major birth defects, a new study shows. There was, however, a small increased risk for certain rare birth defects seen among women who took asthma medication during the month before they conceived through the third month of their pregnancy.

However, the study authors report that it was difficult to discern whether it was the medications or the severity of the asthma that led to these rare defects.

These rare birth defects may include:

  • Incomplete development of the esophagus (esophageal atresia)
  • Missing or blocked opening of the anus (anorectal atresia)
  • Intestines or other organs sticking out of the belly button (omphalocele)

These birth defects are considered extremely rare. The use of asthma drugs such as a bronchodilator or anti-inflammatory drugs such as steroids around the time of conception and during the first trimester increased their risk only slightly.

What’s more, these birth defects could be a result of the asthma, not its treatment.

The new findings study appears in Pediatrics.

Treating the Asthma Is Important

As many as 12% of pregnant women have asthma. The new findings should be seen as reassuring and not alarming for these women, experts tell WebMD.

Researchers analyzed data from the National Birth Defects Prevention Study, including 2,853 infants with one or more select birth defects and 6,726 infants without any birth defects, to see if there was any connection between asthma drugs and risk.

“Many pregnant women with asthma or other diseases fixate on their medications and forget that being sick with the disease can be worse for the fetus,” says Manisha Gandhi, MD. She is a high-risk obstetrician at Baylor College of Medicine in Houston. Gandhi's patients often ask about medication risks, she says.

“The study shows that there are some mild increases in these very rare birth defects,” she tells WebMD.

Do not stop taking your asthma medications because you found out you are pregnant, Gandhi says. “Ideally, if you are thinking about becoming pregnant, talk to your doctor before getting pregnant to make sure your asthma is well-controlled.”

Asthma affects each pregnancy differently, she says. “A third of women get better, a third get worse, and a third stay the same,” she says. There is no way to predict how you will react.

Is It the Asthma or the Medication?

Natalie Meirowitz, MD, agrees that pregnant women with asthma should stay on their medication. She is the chief of maternal fetal medicine at Long Island Jewish Medical Center in New Hyde Park, N.Y.

It may not be the medications that are increasing this risk, but the underlying asthma, she says.

“We really don’t know yet,” Meirowitz tells WebMD.

If it is the asthma, stopping medication may lead to a worsening of the disease and greater risks for the mother and the baby, she says.

If you have any concerns, discuss them with your doctor, but do not stop taking your asthma medications, Meirowitz says.

Even the study authors agree: “The current clinical guidelines and specific recommendation for aggressive asthma management during pregnancy should remain unchanged,” they write.

Show Sources


Manisha Gandhi, MD, Baylor College of Medicine, Houston.

Natalie Meirowitz, MD, chief, division of maternal fetal medicine, Long Island Jewish Medical Center, New Hyde Park, N.Y.

Lin, S. Pediatrics, published online Jan. 16, 2012.

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