By Lynn Martinez and Julia Robertson, CPM, MotherToBaby Utah

During the more than 30 years MotherToBaby affiliates have been serving the public with education regarding exposures during pregnancy, many women have called who are very distressed, sometimes in tears, about finding out they were pregnant while taking a drug categorized as an X or D in the FDA system. “I’ve been on birth control pills and I still got pregnant! Does this mean my baby will have birth defects? It’s a category x drug for goodness sake!” This kind of hysterical reaction was, unfortunately, a common call. It was not unusual to even hear that some of these women had contemplated terminations of otherwise wanted pregnancies. These kinds of misinterpretations are really the opposite of the goal for January’s Birth Defects Prevention Month, “Making Healthy Choices to Prevent Birth Defects.” Confusing drug categories are not leading to healthy choices all of the time. Well, the misinterpretations are all about to change as a new drug labeling rule goes into effect…. What a fresh start to the new year!

But first, a little background…

For decades the Food and Drug Administration (FDA) had been aware of significant problems with the system used to categorize medications for use in pregnancy. In 1992, the Teratology Society, a group of multidisciplinary scientists who study birth defects, expressed concerns and noted that the Category or ‘CAT’ system led to unnecessary terminations of wanted pregnancies1. The FDA Pregnancy Labeling Initiative recommended elimination of the CAT system, changing the label to include more descriptive risk statements and mandating that drug inserts be updated when human information is known.

Before the labeling rule changed just before the new year, when a medication was approved for marketing in the U.S., it had to be labeled with one of five pregnancy CATs: A, B, C, D or X. A meant the drug was well-studied and posed no threat to a developing baby; B was a less-studied, but probably still low-risk drug; C was a drug that had not been studied and therefore the risk was unknown; a D-class drug, based on animal or human data, may have posed a risk; and the X classification meant the drug, based on animal or human data, causes birth defects or there was no benefit for its use during pregnancy. Its use was not recommended in pregnancy.

More than 90 percent of new medications were categorized as either CAT C, D or X, the vast majority being C. Drug manufacturers were legally required to update the category if harmful results were reported; however, no such requirement existed for updating the category when studies showed no problems in pregnancy. Most medications on the market continued to be listed as CAT C, when in fact the majority of them should have been labeled as a CAT A or B. Manufacturers knew that no matter a woman’s history, all pregnancies carried a 3 percent risk of having a child with a major birth defect. Because of this, many manufacturers may have felt better protected from lawsuits if their drugs were listed as CAT C, D, or X. So, really, why would they move up medications in those categories up to A or B? They really didn’t have an incentive.

Moving forward and what it means to mom…

With the FDA rule change, which goes into effect on June 30th of this year, a new set of requirements will be put into place to better inform mom. It now requires the manufacturers to ‘upgrade’ a medication’s labeling when studies show the risk has changed. Also, manufacturers will have to explore various ways of discussing in detail the risks associated with the drug. One expert source that manufacturers could consult is a teratogen information service, like MotherToBaby. More information will help you make more informed choices about your health and pregnancy!

There will still be confusion…

As we see the new labels being implemented, there will still be many drugs on the market with the CAT system since it’ll take time to update all of them. MotherToBaby does not recommend the public or providers rely on the old CAT system for risk assessment. We welcome your questions about the system as well as questions about specific medications in pregnancy and breastfeeding for a complete, personalized risk assessment. Please call us toll-FREE at 866-626-6847. Happy New Year and here’s to a less confusing year of making healthy choices about medications in pregnancy and breastfeeding!

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Lynn Martinez is a Senior Teratogen Information Specialist with MotherToBaby Utah, a program with the health department and University of Utah that aims to educate women about medications and more during pregnancy and breastfeeding. Along with answered questions from women and health providers regarding exposures during pregnancy/breastfeeding via MotherToBaby’s toll-free hotline and email counseling service. Lynn has also traveled around the state educating doctors, nurse midwives, pharmacists and others over the past three decades.

Julia Robertson, CPM, is the program manager for MotherToBaby’s Utah affiliate. She has authored several peer-reviewed publications focusing on maternal medication consumption and the effect on the developing fetus.

MotherToBaby is a service of the international Organization of Teratology Information Specialists (OTIS), a suggested resource by many agencies, including the Centers for Disease Control and Prevention (CDC). If you have questions about medications, alcohol, diseases, vaccines, or other exposures during pregnancy or breastfeeding, call MotherToBaby toll-FREE at 866-626-6847 or browse a library of fact sheets.

1. Friedman, J. Teratology 1993:48:506
2. For more information go to: