Abstract
Some drugs are known for their fetal nephrotoxicity and should be avoided during pregnancy. We report on a pregnant woman suffering from breast cancer who received a weekly neoadjuvant trastuzumab (Herceptin(®)) therapy from 15 weeks of gestation onward, in addition to a 3-weekly carboplatin/docetaxel chemotherapy. Fetal renal insufficiency with anhydramnios and missing visualization of the fetal bladder developed at 21 weeks. After discontinuation of trastuzumab and repeated instillation of amniotic fluid, the amount of amniotic fluid remained stable after 24 weeks of gestation. After caesarean section at 34 weeks because of fetal growth restriction, the renal function of the neonate was normal postnatally. In accordance with the current literature, our case shows a reversible adverse effect of trastuzumab on the fetal renal function and confirms the current recommendation that trastuzumab in pregnancy should be avoided. In pregnancies exposed to trastuzumab, treatment should be discontinued and the fetus should be closely monitored, with particular attention to the amniotic fluid and the fetal bladder volume, as these reflect fetal renal function.