You must not approach a woman to have sexual relations with her during her menstrual period.

Leviticus 12:2
"Say to the Israelites, 'A woman who becomes pregnant and gives birth to a son will be unclean for seven days, as she is during the days of her menstruation.

Leviticus 15:24
If a man lies with her and her menstrual flow touches him, he will be unclean for seven days, and any bed on which he lies will become unclean.

Leviticus 18:18
You must not take your wife's sister as a rival wife and have sexual relations with her while your wife is still alive.

Leviticus 20:18
If a man lies with a menstruating woman and has sexual relations with her, he has exposed the source of her flow, and she has uncovered the source of her blood. Both of them must be cut off from among their people.

2 Samuel 11:4
Then David sent messengers to get her, and when she came to him, he slept with her. (Now she had just purified herself from her uncleanness.) Then she returned home.

Ezekiel 22:10
In you they have uncovered the nakedness of their fathers; in you they violate women during their menstrual impurity.

Also you shall not approach to a woman to uncover her nakedness, as long as she is put apart for her uncleanness.