On the Sabbath one is forbidden to cause harm and the shedding of blood, so the scholars asked: Is one permitted to have sexual intercourse with a virgin on the Sabbath? What would lead to prohibition, and what to permission? Is hymeneal blood like any other wound which leads to the issuance of blood, and therefore one would be forbidden to have intercourse with a virgin on the Sabbath, or is hymeneal blood not the result of a wound to the woman’s body — might it be blood which has gathered inside her, waiting, and so one is permitted to have intercourse with her on the Sabbath?
The scholars were not content with asking only this. They continued: Even if we suppose that hymeneal blood is like any other wound and is the blood shed by a wound, there might still be grounds to permit having intercourse with a virgin on the Sabbath. When should it be permitted? In a case where a man has intercourse with the virgin in order to see the blood and thus know that no man had previously had intercourse with her. But if his intent is to tear her hymen and turn her into a married woman for issues of sexual intercourse and personal law she serves him as a vessel, and one would be forbidden to have sexual intercourse with her on the Sabbath. (Halacha rules that one may have intercourse with a virgin on the Sabbath.)
(Babylonian Talmud, Tractate Ketubot 5b)