The Book of Purification and its Sunnah
1/132. Chapter:
If a girl has menstruated, she should not pray unless she is wearing a head cover
Sunan Ibn Majah
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَعَلِيُّ بْنُ مُحَمَّدٍ، قَالاَ حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنْ عَبْدِ الْكَرِيمِ، عَنْ عَمْرِو بْنِ سَعِيدٍ، عَنْ عَائِشَةَ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ دَخَلَ عَلَيْهَا فَاخْتَبَأَتْ مَوْلاَةٌ لَهَا فَقَالَ النَّبِيُّ ـ صلى الله عليه وسلم ـ " حَاضَتْ " . فَقَالَتْ نَعَمْ . فَشَقَّ لَهَا مِنْ عِمَامَتِهِ فَقَالَ " اخْتَمِرِي بِهَذَا " .
It was narrated from 'Aishah that: The Prophet entered upon her, and a freed slave girl of hers concealed herself. The Prophet asked: "Have her periods begun?" She said: "Yes." He tore a piece of his turban and said: "Cover your head with this."
Reference : Sunan Ibn Majah 654In-book reference : Book 1, Hadith 388English translation : Vol. 1, Book 1, Hadith 654