Pregnant women who have asthma that flares during the first trimester of pregnancy may have a baby with a higher risk of birth defects, according to a new study published in the June Journal of Allergy & Clinical Immunology. Here are the highlights of the study:

• 3,477 women with asthma who had given birth at least once between 1990 and 2000 were included
• Researchers found that women who had an asthma attack, or flare, during the first 3 months of pregnancy were 48% more likely to have a baby with a birth defect
• 13% of babies born to those women had problems with the heart, facial structures, spine or digestive system
• Only 9% of babies born to women with well-controlled asthma had these issues

Poorly controlled asthma is not good for mom’s or baby’s health. It results in a decreased flow of oxygen to the airways and in the blood for mom and to the placenta for baby. Experts believe that this loss of flow of blood and oxygen through the placenta, along with the fact that the first trimester, when much of a fetus’ development is happening, is a sensitive period, may be the explanation for these birth defects.

So, if you have asthma and are thinking of becoming pregnant, it’s important to make sure your asthma is under control first, if you want to give your baby the best chance for good health possible. And during pregnancy, take care to follow your asthma management plan so that control doesn’t slip.

To learn more about the risks associated with pregnancy and asthma, visit our Asthma & Pregnancy article.