In a pregnant patient with threadworm, which statement is correct?

• A. Albendazole is safe in pregnancy
• B. Pyrantel pamoate is safe in pregnancy
• C. Mebendazole is contraindicated in pregnancy
• D. Metronidazole should be avoided in pregnancy

Answer: (D)

When treating threadworm in pregnancy, the priority is to minimize any risk to the fetus by choosing medicines with established fetal safety data. Some antiparasitics carry teratogenic concerns in pregnancy, so their use is avoided or limited.

Metronidazole should be avoided in pregnancy due to potential teratogenic effects, particularly in the first trimester. For pinworm, the other agents have safety caveats: albendazole and mebendazole are typically avoided in pregnancy because of teratogenic concerns noted in animal studies and limited human safety data, especially early in gestation. While pyrantel pamoate is generally considered safe for use in pregnancy and is commonly used for pinworm, the statement that metronidazole should be avoided is the one that aligns with minimizing fetal risk in this context.