Sahih al-Bukhari 329
Sahih al-Bukhari · Book 6: Menstrual Periods · If a woman gets her menses after Tawaf-al-Ifada
Narrated Ibn `Abbas:
حَدَّثَنَا مُعَلَّى بْنُ أَسَدٍ ، قَالَ حَدَّثَنَا وُهَيْبٌ ، عَنْ عَبْدِ اللَّهِ بْنِ طَاوُسٍ ، عَنْ أَبِيهِ ، عَنِ ابْنِ عَبَّاسٍ ، قَالَ رُخِّصَ لِلْحَائِضِ أَنْ تَنْفِرَ، إِذَا حَاضَتْ. وَكَانَ ابْنُ عُمَرَ يَقُولُ فِي أَوَّلِ أَمْرِهِ إِنَّهَا لاَ تَنْفِرُ. ثُمَّ سَمِعْتُهُ يَقُولُ تَنْفِرُ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم رَخَّصَ لَهُنَّ.
A woman is allowed to leave (go back home) if she gets menses (after Tawaf-Al-Ifada). Ibn `Umar formerly used to say that she should not leave but later on I heard him saying, "She may leave, since Allah's Messenger (ﷺ) gave them the permission to leave (after Tawaf-Al-Ifada)."