Abstract
Since their approval, immune checkpoint inhibitors (ICIs) have become the standard of care for multiple malignancies. ICIs enhance tumor destruction by blocking important immunomodulatory pathways that regulate T-cell activation. These pathways include programmed cell death protein-1 and its ligands (programmed cell death protein-1 and programmed death ligand-1, respectively) and cytotoxic T-lymphocyte-associated protein 4. While blocking these pathways can enhance tumor destruction, these pathways are critical for the development of maternal tolerance towards the fetus. Therefore, if ICIs disrupt these immunomodulatory pathways, there could be a maternal immune response against the fetus, as was found in animal studies. With few reported cases of human pregnancy exposure to ICIs, the effects of ICIs on human pregnancy remain largely unknown. Here, we review and summarize the 6 cases of maternal exposure to immunotherapy that have been published before the present study. To add to the evidence, we present a case series of 2 patients who have been exposed to immunotherapy in pregnancy.