We set out at the approach of the new moon of Dhu al-Hijjah. The Messenger of Allah ﷺ said, "Whoever wishes to enter ihram for an Umra, let him do so, for had I not brought the sacrificial animal, I would have entered ihram for an Umra."Some of the people entered ihram for Umra, and others for Hajj. I was among those who entered ihram for Umra. Then the day of Arafah came and I was menstruating, so I complained to the Prophet ﷺ.He said, "Set aside your Umra, undo your hair, comb it, and enter ihram for Hajj."I did so. When the night of Hasbah came, he sent my brother Abd al-Rahman bin Abu Bakr with me, and I went out to Tanim and entered ihram for an Umra in place of my original Umra.
خرجنا موافين لهلال ذي الحجة، فقال رسول الله ﷺ: من أحب أن يهل بعمرة فليهلل؛ فإني لولا أني أهديت لأهللت بعمرة. فأهل بعضهم بعمرة، وأهل بعضهم بحج، وكنت أنا ممن أهل بعمرة، فأدركني يوم عرفة وأنا حائض، فشكوت إلى النبي ﷺ فقال: دعي عمرتك، وانقضي رأسك، وامتشطي وأهلي بحج. ففعلت حتى إذا كان ليلة الحصبة أرسل معي أخي عبد الرحمن بن أبي بكر فخرجت إلى التنعيم فأهللت بعمرة مكان عمرتي.
Bukhari narrated it in "Menstruation" (317) via Abu Usama, and Muslim in "Hajj" (116/1211) via Ibn Numayr, both of them from Hisham bin Urwa, from his father, from Ayesha. The wording given here is Bukhari's.Ibn Majah added (641), with a sahih chain, from Waki, from Hisham bin Urwa with the same chain, "and perform ghusl."Bukhari titled the chapter, "Chapter on a woman undoing her hair for the ghusl of menstruation," which indicates that he considered undoing the hair obligatory for the ghusl of menstruation. Hasan and Tawus held this same view regarding the menstruating woman, but not regarding one in janaba.Abdullah bin Amr held that undoing the hair was obligatory in both cases, as mentioned in Sahih Muslim, and Ayesha objected to this view of his.The majority held that it is not obligatory, based on the hadith of Umm Salama in Sahih Muslim, in which she asked, "Should I undo it for menstruation and janaba?" He said, "No." They interpreted the command in Ayesha's hadith as one of recommendation, in order to reconcile the two hadiths.Ibn Rajab, in his commentary on Bukhari, Fath al-Bari Sharh Sahih Bukhari (1/476), holds that there is no indication in Ayesha's hadith that she undid her hair for the ghusl of menstruation. For the ghusl that the Prophet ﷺ commanded her to perform was not the ghusl of menstruation, rather she was still menstruating at the time, and her menstruation was still ongoing. Had her menstruation ceased, she would have performed tawaf for the umrah and would not have needed to ask this question at all. Rather, he commanded her to perform ghusl while still menstruating and to enter the state of ihram for Hajj. So it was a ghusl for ihram performed while menstruating, just as he commanded Asma bint Umays, when she experienced postpartum bleeding at Zulhulayfa, to perform ghusl and enter the state of ihram.He also said, "Bukhari's intent may be understood in a sound way, namely that the Prophet ﷺ only commanded Ayesha to undo her hair and comb it for the ghusl of ihram, because the ghusl of ihram is not repeated, so undoing the hair for it is not burdensome. This same reasoning applies to the ghusl of menstruation and postpartum bleeding, unlike the ghusl of janaba, which is repeated, so undoing the hair for it would be burdensome. That is why undoing the hair was not commanded for it."