Dr Sushma Tomar, Obstetrician and Gynecologist, Fortis Hospital, Kalyan, adds: "Just like we don't have to tell our heart to pump or direct our lungs to breathe, our immune system functions well without the need for us to intervene. Our immune system is designed to use a host of methods to keep us in good health and defend us from different pathogens. Similarly, menstruation is a monthly exercise in a woman's reproductive system. The immune system in menstruating women also follows a cyclical pattern. While there is blood and tissue loss during the period, it has no impact on the immune system. However, if your bleeding is heavy, you may experience weakness and fatigue, but that again does not stop your immune system from fighting pathogens. We all need to understand that vaccination is an effort and a process to build immunity. It won't decrease your immune response at all. Therefore, women should not be worried about their menstruation and register for their vaccination, as they become eligible."