"It is not permissible for you to get married until four months and ten days, the longer of the two periods, have passed." She went to the Messenger of Allah and asked him about that. She said that the Messenger of Allah ruled that she could get married when she had given birth. She was nine months pregnant when her husband died, and she was married to Sa'd bin Khawlah, who died during the Farewell Pilgrimage with the Messenger of Allah. She married a young man from her people when she had given birth to (the child). (Using translation from Nasāʾī 3519)  

لِسُبَيْعَةَ الْأَسْلَمِيَّةِ لَا تَحِلِّينَ حَتَّى يَمُرَّ عَلَيْكِ أَرْبَعَةُ أَشْهُرٍ وَعَشْرٌ أَقْصَى الْأَجَلَيْنِ فَأَتَتْ رَسُولَ اللهِ ﷺ فَسَأَلَتْهُ عَنْ ذَلِكَ فَزَعَمَتْ أَنَّ رَسُولَ اللهِ ﷺ «أَفْتَاهَا أَنْ تَنْكِحَ إِذَا وَضَعَتْ حَمْلَهَا وَكَانَتْ حُبْلَى فِي تِسْعَةِ أَشْهُرٍ حِينَ تُوُفِّيَ زَوْجُهَا وَكَانَتْ تَحْتَ سَعْدِ بْنِ خَوْلَةَ فَتُوُفِّيَ عَنْهَا فِي حَجَّةِ الْوَدَاعِ مَعَ رَسُولِ اللهِ ﷺ فَنَكَحَتْ فَتًى مِنْ قَوْمِهَا حِينَ وَضَعَتْ مَا فِي بَطْنِهَا»