1,037. Chuppas Niddah

148:2 A virgin is married through seclusion (yichud) even if she is not able to have relations, such as if she is menstruating, or if people are entering and exiting the room. If she is menstruating, then it is required that people come and go because otherwise it would be forbidden for the groom to be alone with her before they have had marital relations for the first time.

148:3 Marrying a widow is only consummated through seclusion that would be suitable for marital relations being possible, i.e., she must be in a state of ritual cleanliness and nobody must enter the room.