Researchers at RMIT University and Monash IVF in Australia have identified a molecule called podocalyxin (PCX) that makes the lining of the uterus resistant to embryo implantation. Levels of this molecule decrease at some point during the menstrual cycle, allowing the uterus to become “sticky” and increasing the likelihood of embryo implantation and pregnancy success. The results of the study showed that women with low levels of PCX have a successful pregnancy rate after IVF of 53%, while women with high levels of PCX have a successful pregnancy rate of 18%. Currently, there is no way to screen an endometrial tissue biopsy for PCX levels on the day the embryo transfer is scheduled to take place. A future goal of the research team is to develop non-invasive, real-time approaches to measure PCX on the day of embryo transfer. In the future, the discovery will help determine exactly when each patient has the best chance of becoming pregnant, providing fully personalized treatment.