Al-Kāfi

Hadith 349
menstruation
3ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنْ عَبْدِ الله بْنِ الْمُغِيرَةِ عَمَّنْ أَخْبَرَهُ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) قَالَ إِذَا كَانَتْ أَيَّامُ الْمَرْأَةِ عَشَرَةَ أَيَّامٍ لَمْ تَسْتَظْهِرْ وَإِذَا كَانَتْ أَقَلَّ اسْتَظْهَرَتْ.
3. Ali ibn Ibrahim has narrated from his father from ‘Abd Allah ibn al-Mughirah from those who narrated to him who have said the following: “Abu ‘Abd Allah (a.s.), has said, ‘If normal duration of a woman’s blood discharge due to Hayd (menses) is ten days, she does not need to perform an examination but if it is less, she must perform an examination.’”
Source: Shaykh Muḥammad b. Yaʿqūb al-Kulaynī