MetroCream and Pregnancy
Although MetroCream (metronidazole cream) is a pregnancy Category B medication, it is unknown whether this skin cream is safe for use during pregnancy. When the active ingredient in MetroCream was given to pregnant animals, it did not appear to cause problems. However, the active ingredient in the medication does pass through the placenta and may increase the risk for childhood cancer.
MetroCream® (metronidazole cream) is a prescription skin medication used for the treatment of rosacea. Even though this product is a pregnancy Category B medication, it is not clear if it is safe for use during pregnancy. There is some concern about the carcinogenic (cancer-causing) potential of metronidazole products, including MetroCream, when used during pregnancy.
The U.S. Food and Drug Administration (FDA) uses a category system to classify the possible risks to a fetus when a specific medicine is taken during pregnancy. Pregnancy Category B is given to medicines that have not been adequately studied in pregnant humans but do not appear to cause harm to the fetus in animal studies.
MetroCream is classified as a pregnancy Category B medication because metronidazole, the active ingredient in it, crosses the placenta. In general, animal studies have failed to show that metronidazole causes problems during pregnancy. However, one study suggested that when this drug was injected into the abdominal (stomach) cavity, it might cause a miscarriage. Surveys and other similar types of studies in humans seem to suggest that metronidazole probably does not cause birth defects.
There is some concern that exposure to metronidazole during pregnancy might increase the risk of childhood (or even adult) cancers. This drug increases the risk of certain cancers in mice and rats; it is unknown if the same is true for humans. Studies have failed to consistently show that metronidazole exposure increases the risk of childhood cancers.
Keep in mind that the absorption of metronidazole through the skin is low, meaning that applying MetroCream is unlikely to cause high levels of the drug to appear in the bloodstream.