"That is a vein, so when your period comes, do not pray, and when your period is over, purify yourself and pray in between one period and the next." This is evidence that Al-Aqra' is menstruation. Abu 'Abdur-Rahman said: Hisham bin 'Urwah reported this Hadith from 'Urwah, and he did not mention what Al-Mundhir mentioned in it.
أَنَّهَا أَتَتْ رَسُولَ اللَّهِ ﷺ فَشَكَتْ إِلَيْهِ الدَّمَ فَقَالَ لَهَا رَسُولُ اللَّهِ ﷺ إِنَّمَا ذَلِكِ عِرْقٌ فَانْظُرِي إِذَا أَتَاكِ قُرْؤُكِ فَلاَ تُصَلِّي فَإِذَا مَرَّ قُرْؤُكِ فَتَطَهَّرِي ثُمَّ صَلِّي مَا بَيْنَ الْقُرْءِ إِلَى الْقُرْءِ هَذَا الدَّلِيلُ عَلَى أَنَّ الأَقْرَاءَ حِيَضٌ قَالَ أَبُو عَبْدِ الرَّحْمَنِ وَقَدْ رَوَى هَذَا الْحَدِيثَ هِشَامُ بْنُ عُرْوَةَ عَنْ عُرْوَةَ وَلَمْ يَذْكُرْ فِيهِ مَا ذَكَرَ الْمُنْذِرُ