A new study on antibiotics and pregnancy may give some relief to expectant moms this flu season.

Most expectant moms are hesitant to take antibiotics. But the medication can be crucial for pregnant women, especially during flu season if their flu turns into pneumonia. And a new study may ease fears for moms-to-be.

Researchers looked at nearly 20,000 mothers and found that antibiotics like penicillin are not associated with most birth defects. Doctors say the findings are important because not treating an infection during pregnancy can put both mother and child at risk.

“Bacterial infections can also have an effect on the pregnancy and result in, for instance, preterm birth and low birth weight,” Jennita Reefhuis with the National Birth Defects Prevention Study said.

The study did link two antibiotics, sulfonamides and nitrofurantoins, to a number of severe birth defects.

Those medications are commonly used to treat urinary tract infections.