The FDA wants to replace a 30-year-old system for classifying drugs taken during pregnancy and breastfeeding in in favor of labels that provide more detailed info about risks and benefits. Women take an average of three to five meds during pregnancy and more than 90 percent of nursing mothers take medication during the first week after delivery, USA Today notes.

And because half of the nation’s 6 million annual pregnancies are unplanned, many women take medications before they realize they’re pregnant, but current drug labels offer little help in assessing the risks to a baby who already has been exposed, according to Sandra Kweder, deputy director of the FDA’s office of new drugs.

The agency says drugmakers haven’t done a good job of keeping up-to-date labeling info on risks and benefits that a drug presents to pregnant women, so its proposed rule should prompt pharma to kepe labels current. The proposed label changes may also cause the FDA to scrutinize the approval process for the effects a drug may have on pregnant women and fetuses, according to Kweder.