Hefsek Taharah

A woman becomes niddah from the moment that blood exits the uterus and enters the vaginal canal, even before it leaves her body. Therefore, in order to confirm that all uterine bleeding has ceased, she must do an internal examination, or bedikah. This examination is called a hefsek taharah, which literally means that she has stopped bleeding and can begin the process of exiting the niddah status.