2,052. If the Expected Time Has Passed

Hilchos Issurei Biah 4:13

If the time when a woman expected her period passed and it didn’t arrive, she is permitted to be intimate. For example, if her period normally began after six hours of the day, she may not be intimate starting from the beginning of the day. If six hours pass without her period arriving, she remains prohibited until the evening. Similarly, if her period normally began after six hours of the night and that time passed without it arriving, she remains prohibited until sunrise.

Hilchos Issurei Biah 4:14

The practice of the Jewish people is to inspect themselves after intimacy, each participant using a cloth prepared for this purpose, to ensure whether the woman may have bled during relations. The man may allow the woman to check using his cloth; since her word is accepted regarding her own cloth, it is also accepted regarding his.