Muwatta Malik 130
Purity
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَائِشَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم قَالَتْ فِي الْمَرْأَةِ الْحَامِلِ تَرَى الدَّمَ أَنَّهَا تَدَعُ الصَّلاَةَ .
Yahya related to me from Malik that he had heard that A'isha, the wife of the Prophet, may Allah bless him and grant him peace, said that a pregnant woman who noticed bleeding left off from prayer
Grading: Salim al-Hilali: Mauquf Hasan
Text from the public-domain hadith-api dataset. Numbering follows that dataset and can differ by a few from some printed editions — check the wording, not only the number.