Once one of the wives of the Prophet ﷺ did Iʿtikaf along with him and she was getting bleeding in between her periods. She used to see the blood (from her private parts) and she would perhaps put a dish under her for the blood. (The sub-narrator ʿIkrima added, ʿAisha once saw the liquid of safflower and said, "It looks like what so and so used to have.") (Using translation from Bukhārī 309)
أَنَّ رَسُولَ اللهِ ﷺ اعْتَكَفَ فَاعْتَكَفَتْ مَعَهُ بَعْضُ نِسَائِهِ وَهِيَ مُسْتَحَاضَةٌ تَرَى الدَّمَ فَرُبَّمَا وُضِعَتِ الطَّسْتُ تَحْتَهَا مِنَ الدَّمِ وَزَعَمَ أَنَّ عَائِشَةَ رَأَتْ مَاءَ الْعُصْفُرِ فَقَالَتْ كَانَ هَذَا شَيْئًا كَانَتْ فُلَانَةُ تَجِدُهُ لَفْظُ وَهْبٍ وَحَدِيثُ إِسْحَاقَ مِثْلُهُ سَوَاءٌ