4 Then David sent messengers to get her. She came to him, and he slept with her. (Now she was purifying herself from her monthly uncleanness.) Then she went back home.

Read 2 Samuel 11:4 Using Other Translations

And David sent messengers, and took her; and she came in unto him, and he lay with her; for she was purified from her uncleanness: and she returned unto her house.
So David sent messengers and took her, and she came to him, and he lay with her. (Now she had been purifying herself from her uncleanness.) Then she returned to her house.
Then David sent messengers to get her; and when she came to the palace, he slept with her. She had just completed the purification rites after having her menstrual period. Then she returned home.