Leviticus 15:19

19 “ ‘When a woman has her regular flow of blood, the impurity of her monthly period will last seven days, and anyone who touches her will be unclean till evening.

Read Leviticus 15:19 Using Other Translations

And if a woman have an issue, and her issue in her flesh be blood, she shall be put apart seven days: and whosoever toucheth her shall be unclean until the even.
"When a woman has a discharge, and the discharge in her body is blood, she shall be in her menstrual impurity for seven days, and whoever touches her shall be unclean until the evening.
“Whenever a woman has her menstrual period, she will be ceremonially unclean for seven days. Anyone who touches her during that time will be unclean until evening.