It was narrated that Umm Salamah said:"I was with the Messenger of Allah under his blanket, then I felt that I was menstruating as women do, so I slipped out from under the cover. The Messenger of Allah said: 'Are you menstruating?' I said: 'I feel that I am menstruating as women do.' He said: 'That is what Allah has decreed for the daughters of Adam.' So I slipped out and sorted myself out, then I came back, and the Messenger of Allah said to me: 'Come under the cover with me,' so I went in with him.'"
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ بِشْرٍ، حَدَّثَنَا مُحَمَّدُ بْنُ عَمْرٍو، حَدَّثَنَا أَبُو سَلَمَةَ، عَنْ أُمِّ سَلَمَةَ، قَالَتْ كُنْتُ مَعَ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ فِي لِحَافِهِ فَوَجَدْتُ مَا تَجِدُ النِّسَاءُ مِنَ الْحَيْضَةِ فَانْسَلَلْتُ مِنَ اللِّحَافِ فَقَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " أَنَفِسْتِ " . قُلْتُ وَجَدْتُ مَا تَجِدُ النِّسَاءُ مِنَ الْحَيْضَةِ . قَالَ " ذَلِكَ مَا كَتَبَ اللَّهُ عَلَى بَنَاتِ آدَمَ " . قَالَتْ فَانْسَلَلْتُ فَأَصْلَحْتُ مِنْ شَأْنِي ثُمَّ رَجَعْتُ فَقَالَ لِي رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " تَعَالَىْ فَادْخُلِي مَعِي فِي اللِّحَافِ " . قَالَتْ فَدَخَلْتُ مَعَهُ .
IbnMaja
The Book of Purification and its Sunnah • Hadith 637