Pregnant and worried about your medication? The Food and Drug Administration is revamping confusing labels on prescription drugs to make it easier to understand which medications may pose risks to the baby.

Women take an average of three to five prescription drugs during pregnancy, for everything from asthma to infections. It's hard to tell which are safest, or even if they'll require a different dose. The letters A, B, C, D and X are used to convey risk, but FDA acknowledges that's misleading.

On Wednesday, FDA announced it is scrapping that system. Starting next summer, labels on new prescription drugs must clearly state what's known about safe use during pregnancy or breastfeeding, including whether the information comes from studies in people or only in animals. Older drugs will phase in the new labels.