I prayed behind the Messenger of Allah ﷺ and he prayed for a woman who had died in the state of delivery. He stood in front of her waist.  

صَلَّيْتُ خَلْفَ النَّبِيِّ ﷺ وَصَلَّى عَلَى أُمِّ كَعْبٍ مَاتَتْ وَهِيَ نُفَسَاءُ فَقَامَ رَسُولُ اللَّهِ ﷺ لِلصَّلاَةِ عَلَيْهَا وَسَطَهَا  

This hadith has been narrated by Husain with the same chain of transmitters, but no mention is made of Umm Ka'b.  

عَنْ حُسَيْنٍ بِهَذَا الإِسْنَادِ وَلَمْ يَذْكُرُوا أُمَّ كَعْبٍ  

I was a young boy during the time of the Prophet ﷺ and I retained in my mind (what I learnt from him), and nothing restrained me from speaking except the fact that there were persons far more advanced in age than I. Verily, I said prayer behind the Messenger of Allah ﷺ over a woman who had died in the state of delivery, and the Messenger of Allah ﷺ stood up to say prayer in front of the middle part of her body. And in the tradition narrated on the authority of Ibn Muthanna the words are:" (The Holy Prophet) stood in the middle part of her body for offering prayer for her."  

سَمُرَةُ بْنُ جُنْدُبٍ لَقَدْ كُنْتُ عَلَى عَهْدِ رَسُولِ اللَّهِ ﷺ غُلاَمًا فَكُنْتُ أَحْفَظُ عَنْهُ فَمَا يَمْنَعُنِي مِنَ الْقَوْلِ إِلاَّ أَنَّ هَا هُنَا رِجَالاً هُمْ أَسَنُّ مِنِّي وَقَدْ صَلَّيْتُ وَرَاءَ رَسُولِ اللَّهِ ﷺ عَلَى امْرَأَةٍ مَاتَتْ فِي نِفَاسِهَا فَقَامَ عَلَيْهَا رَسُولُ اللَّهِ ﷺ فِي الصَّلاَةِ وَسَطَهَا وَفِي رِوَايَةِ ابْنِ الْمُثَنَّى قَالَ حَدَّثَنِي عَبْدُ اللَّهِ بْنُ بُرَيْدَةَ قَالَ فَقَامَ عَلَيْهَا لِلصَّلاَةِ وَسَطَهَا