عَنْ مَيْمُونَةَ (زَوْجِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ) أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ كَانَ يُبَاشِرُ الْمَرْأَةَ مِنْ نِسَائِهِ وَهِيَ حَائِضٌ، إِذَا كَانَ عَلَيْهَا إِزَارٌ يَبْلُغُ أَنْصَافَ الْفَخِذَيْنِ أَوِ الرُّكْبَتَيْنِ مُحْتَجِزَةً بِهِ
It is narrated from the wife of the Messenger, Sayyida Maymunah (may Allah be pleased with her), that the Messenger of Allah (peace and blessings be upon him) used to join his body with the body of his wives who were menstruating, while there was (at least) such a lower garment on her that reached halfway down the thighs or up to the knees, and she would thus protect (the private area) with it.