I used to spend the night with the Messenger of Allah ﷺ under the same garment while I was menstruating. If anything from me got onto it, he would wash that spot only and would not go beyond it, then he would pray in it.
حدثنا يحيى عن جابر بن صبح قال سمعت خلاسا قال سمعت
كنت أبيت أنا ورسول الله ﷺ في الشعار الواحد وأنا طامث حائض قالت فإن أصابه مني شيء غسله لم يعد مكانه وصلى فيه
Its isnad is sahih. Jabir bin Sabih is Rasibi, whose hadith is deemed reliable in the Sunan works, and Khilas is Ibn Amr Hajari, who is trustworthy and whose hadith is accepted by the group [of six hadith compilers]. The hadith was narrated by Abu Dawud, 1/70, no. 269, in the book of purification, and by Nasai, 1/188, no. 372, and by Bayhaqi, 1/313, both in the book of menstruation.