Women's Healthcare Topics

FDA Medicine Categories for Pregnancy Safety

Reviewed by James Brann, M.D.

FDA Classification System

Learn which FDA Medicine Categories are safe in pregnancy.

During pregnancy, medicine can cross the placenta and enter your baby's blood stream. While some medications are perfectly safe to take and won't harm your baby, others can lead to birth defects, miscarriage, stillbirths, and reduced fetal growth. They may also impair or halt the development of important organs, including your baby's central nervous system.

Medicine, both over-the-counter and prescription, can impact your baby at different stages of his or her development.


They may be more dangerous in the beginning of the pregnancy, but safer closer to your due date. If you are on prescription medication, your doctor may take you off your regular medicine and put you on another medication that is safer for your unborn baby.

The FDA (U.S. Food and Drug Administration) requires that all drugs list their risks for pregnant women and women trying to get pregnant. Before you take any new medications, read the warning labels carefully. Your doctor, nurse, and pharmacist can assist you in finding the medications that are safe to take during pregnancy.

The FDA has a unique classification for drug safety during pregnancy. They include the following:

  • Category A – The drug is completely safe during pregnancy. Controlled studies did not find a risk to the baby in the first trimester, and there is no evidence of harm in the later trimesters.

  • Category B – The medicine is considered safe for pregnant women. Drugs in this category fall into two situations: (1) Animal studies have not shown a risk to the baby or (2) animal studies have shown a negative effect but it was not replicated in controlled studies of women in the first trimester. There is no evidence of risk in later trimesters.

  • Category C – The medicine is possibly harmful to babies, and they should only be given if the potential benefit justifies the risk to the developing baby. Category C drugs have either (1) proven to harm babies in the womb through animal studies, and there are no controlled studies in humans, or (2) the drug has not been studied in women or animals.

  • Category D – There is strong evidence the drug harms unborn babies, but the benefits of use may be acceptable if it outweighs the risk. For example, the drug may be required in a life-threatening situation or serious disease, and no safer drugs can be used.

  • Category X – The drug should never be used in pregnancy. Studies in animals or humans have indicated that the drug causes birth defects. The risks of the medicine clearly outweigh any benefits.

Most "safe" medicines in pregnancy are classified with B or C. Tylenol (acetaminophen) is considered the "safest" pain reliever in pregnancy. Although it does cross the placenta, it's the safest option. Aspirin isn't recommended, except for specific situations, and it's generally considered a Category D drug. Ibuprofen (Advil) and Naproxen aren't recommended, and they should be avoided – especially in the third trimester.

If you are on prescription medication, you should weigh the risk of taking your medication against the effect of not taking them. For example, some diseases are more harmful to your baby than the drugs used to treat them.

You may want to stay away from herbal products, minerals, amino acids, and other "natural" products during pregnancy. These have not been proven safe for pregnant women and women who are nursing. You may want to ask your doctor or healthcare provider about taking these.

Because no medication is 100 percent safe, it is always best to stay away from taking medicine when you are pregnant, unless it is absolutely necessary.

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