Muwatta Malik, Book 2, Hadith 110 (USC-MSA)

Yahya related to me from Malik from Hisham ibn Urwa that his father said, "A woman who bleeds as if menstruating only has to do one ghusl, and then after that she does wudu for each prayer." Yahya said that Malik said, "The position with us is that when a woman who bleeds as if menstruating starts to do the prayer again, her husband can have sexual intercourse with her. Similarly, if a woman who has given birth sees blood after she has reached the fullest extent that bleeding normally restrains women, her husband can have sexual intercourse with her and she is in the same position as a woman who bleeds as if menstruating." Yahya said that Malik said, "The position with us concerning a woman who bleeds as if menstruating is founded on the hadith of Hisham ibn Urwa from his father, and it is what I prefer the most of what I have heard about the matter."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، أَنَّهُ قَالَ لَيْسَ عَلَى الْمُسْتَحَاضَةِ إِلاَّ أَنْ تَغْتَسِلَ غُسْلاً وَاحِدًا ثُمَّ تَتَوَضَّأُ بَعْدَ ذَلِكَ لِكُلِّ صَلاَةٍ ‏.‏ قَالَ يَحْيَى قَالَ مَالِكٌ الأَمْرُ عِنْدَنَا أَنَّ الْمُسْتَحَاضَةَ إِذَا صَلَّتْ أَنَّ لِزَوْجِهَا أَنْ يُصِيبَهَا وَكَذَلِكَ النُّفَسَاءُ إِذَا بَلَغَتْ أَقْصَى مَا يُمْسِكُ النِّسَاءَ الدَّمُ فَإِنْ رَأَتِ الدَّمَ بَعْدَ ذَلِكَ فَإِنَّهُ يُصِيبُهَا زَوْجُهَا وَإِنَّمَا هِيَ بِمَنْزِلَةِ الْمُسْتَحَاضَةِ ‏.‏ قَالَ يَحْيَى قَالَ مَالِكٌ الأَمْرُ عِنْدَنَا فِي الْمُسْتَحَاضَةِ عَلَى حَدِيثِ هِشَامِ بْنِ عُرْوَةَ عَنْ أَبِيهِ وَهُوَ أَحَبُّ مَا سَمِعْتُ إِلَىَّ فِي ذَلِكَ ‏.‏

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also referenced under: Book 2, Hadith 139 (In-Book)