Background: Herceptin (trastuzumab), a new a chemotherapeutic agent, is a monoclonal antibody that blocks the human epidermal growth factor receptor 2 protein. There is no reported experience with use of this agent during pregnancy and possible effects on the fetus.
Case: A patient with breast cancer was treated with Herceptin during pregnancy. This treatment was associated with anhydramnios, which resolved slowly after the drug was discontinued.
Conclusion: Although listed as a category B drug, experience with Herceptin in human pregnancy is limited, and it should be used with caution. Investigation of the role of human epidermal growth factor receptor 2 protein in the embryonic kidney may further our understanding of amniotic fluid dynamics.