2,137. Dam Besulim Nowadays

Hilchos Issurei Biah 11:7

The Rambam says that he heard that in France, even in his day, they permitted marital intimacy after pure blood as was the case in Talmudic times, so long as the woman counted seven days and immersed in a mikvah to rid herself of the ritual impurity conveyed by giving birth as a zavah. This is a matter of accepted local practice.

Hilchos Issurei Biah 11:8

The same stringency applies to hymeneal blood nowadays. Even if a minor is younger than would be expected to get her period, and she never before experienced bleeding, her husband must separate from her after the wedding night. As long as she sees blood from the wound, she is ritually unclean. When the bleeding stops, she counts seven clean days.