Whattoexpect.com: Antibiotics during pregnancy could increase a child’s risk of asthma

Sara Novak | Posted: March 23, 2015

Summary: The prevalence of asthma has doubled over the past 30 years in developed countries and as a result, researchers have been looking into what may be causing this dramatic increase. Past research has linked antibiotic use in babies to childhood allergies, and now new research has found that moms who take antibiotics during pregnancy could be increasing their baby's risk of developing asthma.

Being sick during pregnancy isn't any fun. You're already coping with pregnancy symptoms like swollen feet and heartburn, and now you have to worry about keeping your baby-to-be healthy when you're feeling under the weather. But a new study finds that moms-to-be should resist the urge to take antibiotics unless they can't get well without them, because taking antibiotics during pregnancy may increase the risk of a baby developing asthma.

new study, published in the Annals of Allergy, Asthma and Immunology (ACAAI), followed 298 mother/child pairs through the baby's third year of life. Participants were from disadvantaged families in urban Chicago, and the kids were all at an increased risk for developing asthma (the parents had asthma, hay fever or eczema). Researchers found that 103 children were born to moms who had taken antibiotics during pregnancy. Of those children, 22 percent were diagnosed with asthma by age 3. The kids born to mothers who did not take antibiotics during pregnancy, on the other hand, were half as likely to develop asthma. What's more, a link between antibiotic use and childhood asthma was even present in kids whose moms who did not have asthma. The data suggests that antibiotics could change the maternal and placental microbiome (bacterial makeup of mom and baby in utero), causing issues with a baby's immune system development. This, in turn, could increase risk factors for allergic illnesses.

"The more we know about what factors increase the probability of asthma developing, the better we can assist our pregnant patients," said allergist Dennis Ownby, MD, ACAAI Fellow and study co-author. "We wouldn't recommend not giving antibiotics to a pregnant woman, but we recommend caution when symptoms are not clearly caused by a bacterial infection. Pregnant women with asthma should work with their allergist to create a healthy outcome for themselves and their children."

Researchers also looked at instances of eczema, exercise-induced asthma, sleep disturbances due to wheezing, wheezing without a cold, emergency room visits related to breathing problems and other respiratory illnesses in the first three years of life. Eczema and other respiratory illnesses were increased with the use of antibiotics in utero. However, the use of antibiotics and wheezing were only weakly linked. Maternal asthma and early childhood antibiotic use were also found to increase the risk of a child developing asthma.

The study did have some limitations in that it only included a highly disadvantaged group of participants already at risk for asthma and allergies. What's more, researchers contend that it's difficult to fully assess a disease's progression before 6 years of age, and this study only followed participants until age 3. The study also should have looked at the types of antibiotics used to know whether particular types were more likely to cause asthma.

More reasons to avoid unnecessary antibiotics during pregnancy: Other research has shown that when babies are exposed to antibiotics in infancy, they're more likely to develop food allergies. The overuse of antibiotics also allows some microorganisms to adapt so they no longer respond to medication, resulting in two million infections to antibiotic-resistant bacteria per year in the U.S. And when antibiotics aren't required, they can cause uncomfortable side effects like rash and diarrhea.

What this means to you. If you're sick and need an antibiotic to cure your infection, take it! It will protect both you and your baby. Just keep in mind that antibiotics can only treat bacterial infections like strep throat, bacterial skin infections, bacterial pneumonia and bladder infections. They cannot, however, treat viral infections, including both the common cold and the flu. That means you shouldn't take antibiotics if you're sick with a virus. If your healthcare provider prescribes an antibiotic, ask if it's essential.

Keep in mind, too, that antibiotics are also in places you might not expect, including antibacterial soaps, body washes and other personal care products like toothpaste and makeup. Antimicrobial chemicals found in these products have also been linked to food and environmental allergies. Since these antibiotics aren't necessary to protect your health, they're the easiest place to start trying to avoid antibiotics — so don't buy products with "triclosan" or "triclocarbon" on the label.