וְאִשָּׁה֙ כִּֽי־תִהְיֶ֣ה זָבָ֔ה דָּ֛ם יִהְיֶ֥ה זֹבָ֖הּ בִּבְשָׂרָ֑הּ שִׁבְעַ֤ת יָמִים֙ תִּהְיֶ֣ה בְנִדָּתָ֔הּ וְכָל־הַנֹּגֵ֥עַ בָּ֖הּ יִטְמָ֥א עַד־הָעָֽרֶב

When a woman has a discharge, her discharge being blood from her body, she shall remain in her impurity seven days; whoever touches her shall be unclean until evening. 

Leviticus 15:19