Metoprolol and Pregnancy
In animal studies that looked at pregnancy and metoprolol, problems were seen with the developing fetus. Because of this potential risk, metoprolol is classified as a pregnancy Category C medicine, which means it should be prescribed only if a healthcare provider believes that the benefits to the pregnant woman outweigh the possible risks to the unborn child.
Depending on your particular situation, your healthcare provider may or may not recommend that you take metoprolol (available as Lopressor® and Toprol-XL®) during pregnancy. Metoprolol is considered a pregnancy Category C medicine by the U.S. Food and Drug Administration (FDA), which means that the drug has not been studied in pregnant women. However, when studied in pregnant animals, problems were seen with the unborn fetus. This means there may be an increased risk to the fetus if metoprolol is used during pregnancy. Your healthcare provider will consider the risk of metoprolol, the risk of not treating your condition, and alternative treatment options before making a recommendation.
The FDA uses a category system to classify the possible risks to a fetus when a specific medicine is taken during pregnancy. Pregnancy Category C is given to medicines that have not been studied in pregnant humans but that show side effects to the fetus during animal studies. These side effects can either be temporary (such as a slowed heart rate at birth) or, in some cases, permanent (birth defects). Also, medicines that have not been studied in any pregnant women or animals are automatically given a pregnancy Category C rating.
A pregnancy Category C medicine may still be given to a pregnant woman if the healthcare provider believes that the benefits to the woman outweigh the possible risks to the unborn child. For example, untreated high blood pressure during pregnancy carries its own set of significant risks to both the mother and the fetus (see Preeclampsia). In situations like this, a healthcare provider may prescribe a pregnancy Category C medicine if the benefit of treating high blood pressure in pregnancy outweighs the risk the medicine presents.