Muwatta Imam Malik Book of Purity, Hadith 102

Yahya related to me from Malik that he had heard that A'isha, the wife of the Prophet ﷺ said that a pregnant woman who noticed bleeding left off from prayer.

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَائِشَةَ، زَوْجَ النَّبِيِّ ﷺ قَالَتْ فِي الْمَرْأَةِ الْحَامِلِ تَرَى الدَّمَ أَنَّهَا تَدَعُ الصَّلاَةَ .