"She should observe 'Iddah for the longer of the two periods." Abu Salamah said: "No, it becomes permissible for her to marry when she has given birth." Abu Hurairah said: "I agree with my brother's son." So they sent word to Umm Salamah, the wife of the Prophet, and she said: "Subai'ah Al-Aslamiyyah gave birth shortly after her husband died; she consulted the Messenger of Allah and he told her to get married." (Using translation from Nasāʾī 3512)
أَبُو هُرَيْرَةَ أَنَا مَعَ ابْنِ أَخِي فَأَرْسَلُوا إِلَى أُمِّ سَلَمَةَ زَوْجِ النَّبِيِّ ﷺ فَقَالَتْ وَضَعَتْ سُبَيْعَةُ الْأَسْلَمِيَّةُ بَعْدَ وَفَاةِ زَوْجِهَا بِيَسِيرٍ فَاسْتَفْتَتْ رَسُولَ اللهِ ﷺ «فَأَمَرَهَا أَنْ تَتَزَوَّجَ»