"I heard Naji, claim that Ibn 'Umar offered the funeral prayer for nine together. He put the men closer to the Imam and the women closer to the Qiblah, and he placed them (the women) in one row. And the body of Umm Kulthum bint 'Ali the wife of 'Umar bin Al-Khattab, and a son of hers called Zaid were placed together. The Imam that day was Saeed bin Al-As and among the people were Ibn 'Umar, Abu Hurairah, Abu Saeed and Abu Qatadah. The boy was placed closer to the Imam. A man said something objecting to that, so I looked at Ibn 'Abbas, Abu Hurairah, Abu Saeed and Abu Qatadah and said: 'What is this?' They said: 'It is the Sunnah."  

رَجُلٌ فَأَنْكَرْتُ ذَلِكَ فَنَظَرْتُ إِلَى ابْنِ عَبَّاسٍ وَأَبِي هُرَيْرَةَ وَأَبِي سَعِيدٍ وَأَبِي قَتَادَةَ فَقُلْتُ مَا هَذَا قَالُوا هِيَ السُّنَّةُ  

That the Messenger of Allah offered the funeral prayer for a mother who had died in childbirth, and he stood in line with her middle.  

أَنَّ رَسُولَ اللَّهِ ﷺ صَلَّى عَلَى أُمِّ فُلاَنٍ مَاتَتْ فِي نِفَاسِهَا فَقَامَ فِي وَسَطِهَا