(10) باب اعْتِكَافِ الْمُسْتَحَاضَةِ
Narrated `Aisha:
One of the wives of Allah's Messenger (ﷺ) practiced I`tikaf with him while she ad bleeding in between her periods and she would see red (blood) or yellowish traces, and sometimes we put a tray beneath her when she offered the prayer.
Reference: Sahih al-Bukhari 2037
In-book reference: Book 33, Hadith 12
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 33, Hadith 253