Seven Blood-Free Days (Shivah Neki'im)
Beginning the night after the hefsek taharah, a woman counts seven blood-free days (shivah neki'im) before immersing in the mikveh. During these days she performs internal examinations (bedikot) to confirm that bleeding has not recurred. She also wears white underpants to ensure that she is aware of any staining. After she has completed her shivah neki'im, she may immerse in the mikveh.