Musannaf Ibn Abi Shaybah

Ibrahim says that if a woman observing i'tikaf gets her period, she should put up a curtain in her house and stay there.

Hazrat Abu Qilabah says that if a woman sitting in i'tikaf gets her menses, she should stay by pitching a tent at the door of the mosque.

Hazrat Ikrimah narrates that one of the wives of the Noble Prophet (peace and blessings be upon him) used to observe i'tikaf while in the state of menstruation.