Leviticus 15:25-26

15:25 “‘When a woman’s discharge of blood flows many days not at the time of her menstruation, or if it flows beyond the time of her menstruation, all the days of her discharge of impurity will be like the days of her menstruation – she is unclean. 15:26 Any bed she lies on all the days of her discharge will be to her like the bed of her menstruation, any furniture she sits on will be unclean like the impurity of her menstruation,

Leviticus 15:30

15:30 and the priest is to make one a sin offering and the other a burnt offering. So the priest is to make atonement for her before the Lord from her discharge of impurity.