What is the contraindication for Ondansetron during pregnancy?

Ondansetron is classified as a Category B medication during pregnancy. This classification indicates that animal studies have shown no evidence of harm to the fetus, and there are no well-controlled studies in pregnant women, but the benefits may outweigh the potential risks in certain situations. Although ondansetron is generally considered safe for use in pregnant women, healthcare providers often make decisions based on a careful assessment of the benefits versus possible risks.

Understanding the classification of medications is crucial during pregnancy, as it helps healthcare professionals assess safety for the developing fetus. Category B suggests a relative safety compared to other categories where risks might be more pronounced, such as Category D medications, which indicate positive evidence of risk to human fetuses. Categories A and C also differ in their implications, with Category A being the safest and Category C indicating that risks cannot be ruled out.