Musnad Ahmad 1153:980

'Affan narrated to us, he said: Yazid bin Zuray' narrated to us, he said: Khalid narrated to us, from 'Ikrimah, from 'Aishah, she said: "One of the wives of the Messenger of Allah (peace and blessings of Allah be upon him) performed I'tikaf with him while she was suffering from prolonged menstrual bleeding (istihada). She used to see yellow and red discharge, and we would sometimes place a basin beneath her while she was praying."