If a woman gives birth, She should refrain from prayer for ten days, unless She becomes pure (stops bleeding) before that. If the bleeding continues, She should refrain from prayer for up to eighteen days, because Asma bint Umays experienced postnatal bleeding (nifas) with Muhammad ibn Abi Bakr during the Farewell Pilgrimage, and the Messenger of Allah صلى الله عليه وعلى آله وسلم instructed her to refrain for eighteen days.
Commentary #8