Translation
(41) Types of Blood-Wit (Kitab Al-Diyat)
كتاب الديات
(1665) Chapter: The Diyah For A Fetus
(21) باب دِيَةِ الْجَنِينِ
Sunan Abi Dawud 4573 

Narrated Tawus:

Umar stood on the pulpit. He then mentioned the rest of the tradition to the same effect as mentioned before. He did not mention "that she should be killed". This version adds: "a male or a female slave". Umar then said: Allah is Most Great. Had I not heard it, we would have decided about it something else.

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ الزُّهْرِيُّ، حَدَّثَنَا سُفْيَانُ، عَنْ عَمْرٍو، عَنْ طَاوُسٍ، قَالَ قَامَ عُمَرُ رضى الله عنه عَلَى الْمِنْبَرِ فَذَكَرَ مَعْنَاهُ لَمْ يَذْكُرْ وَأَنْ تُقْتَلَ ‏.‏ زَادَ بِغُرَّةٍ عَبْدٍ أَوْ أَمَةٍ ‏.‏ قَالَ فَقَالَ عُمَرُ اللَّهُ أَكْبَرُ لَوْ لَمْ أَسْمَعْ بِهَذَا لَقَضَيْنَا بِغَيْرِ هَذَا ‏.‏
Grade :  Da'if in chain (Al-Albani) ضعيف الإسناد  (الألباني)حكم :
Reference : Sunan Abi Dawud 4573
In-book reference : Book 41, Hadith 80
English translation : Book 40, Hadith 4556