This project consists of a data repository that will be used to define normal ranges and diagnostic cut-offs for all PCOS diagnostic features using individual participant data (IPD) from unselected populations around the world. It includes data of over 10,000 participants within the age range of 15 to 80 years from various PCOS research collaborating centres in China, USA, Italy, South Korea, Iran, Turkey, Russia and Nigeria. With evolving and new evidence, more collaborations are anticipated.</p