'Umar asked about the decision of the Prophet ﷺ about that (i.e. abortion). Haml b. Malik b. al-Nabhigah got up and said: I was between two women. One of them struck another with a rolling-pin killing both her and what was in her womb. So the Messenger of Allah ﷺ gave judgement that the bloodwit for the unborn child should be a male or a female slave of the best quality and the she should be killed. Abu Dawud said: Al-Nadr b. Shumail said: Mistah means a rolling-pin. Abu Dawud said: Abu 'Ubaid said: Mistah means a pole from the tent-poles.  

عَنْ قَضِيَّةِ النَّبِيِّ ﷺ فِي ذَلِكَ فَقَامَ إِلَيْهِ حَمَلُ بْنُ مَالِكِ بْنِ النَّابِغَةِ فَقَالَ كُنْتُ بَيْنَ امْرَأَتَيْنِ فَضَرَبَتْ إِحْدَاهُمَا الأُخْرَى بِمِسْطَحٍ فَقَتَلَتْهَا وَجَنِينَهَا فَقَضَى رَسُولُ اللَّهِ ﷺ فِي جَنِينِهَا بِغُرَّةٍ وَأَنْ تُقْتَلَ  

he asked the people about the ruling of the Prophet ﷺ concerning that - concerning a fetus. Hamal bin Malik bin Nabighah stood up and said: “I was between my two wives and one of them struck the other with a tent-pole, killing her and a fetus. The Messenger of Allah ﷺ ruled that the blood money for the fetus was a slave, and that she would be killed in retaliation.”  

أَنَّهُ نَشَدَ النَّاسَ قَضَاءَ النَّبِيِّ ﷺ فِي ذَلِكَ يَعْنِي فِي الْجَنِينِ فَقَامَ حَمَلُ بْنُ مَالِكِ بْنِ النَّابِغَةِ فَقَالَ كُنْتُ بَيْنَ امْرَأَتَيْنِ لِي فَضَرَبَتْ إِحْدَاهُمَا الأُخْرَى بِمِسْطَحٍ فَقَتَلَتْهَا وَقَتَلَتْ جَنِينَهَا فَقَضَى رَسُولُ اللَّهِ ﷺ فِي الْجَنِينِ بِغُرَّةٍ عَبْدٍ وَأَنْ تُقْتَلَ بِهَا  

[Machine] "He witnessed the judgment of the Prophet peace be upon him regarding that, then Hamal bin Malik bin al-Nabighah came and said, 'I was between two women when one of them hit the other with a flat object, causing her death along with her unborn child.' The Prophet peace be upon him presided over the case and ruled to compensate for the loss of the unborn child with a male servant. When I said this to 'Amr, Ibn Tawus informed me about his father, saying such and such.' 'Amr said, 'You have made me doubtful.' Ibn Bakr said, 'I was between two women when one of them hit the other.'"  

أَنَّهُ شَهِدَ قَضَاءَ النَّبِيِّ ﷺ فِيذَلِكَ فَجَاءَ حَمَلُ بْنُ مَالِكِ بْنِ النَّابِغَةِ فَقَالَ كُنْتُ بَيْنَ امْرَأَتَيْنِ فَضَرَبَتْ إِحْدَاهُمَا الْأُخْرَى بِمِسْطَحٍ فَقَتَلَتْهَا وَجَنِينَهَا فَقَضَى النَّبِيُّ ﷺ فِي جَنِينِهَا بِغُرَّةٍ عَبْدٍ وَأَنْ تُقْتَلَ فَقُلْتُ لِعَمْرٍو أَخْبَرَنِي ابْنُ طَاوُسٍ عَنْ أَبِيهِ كَذَا وَكَذَا فَقَالَ لَقَدْ شَكَّكْتَنِي قَالَ ابْنُ بَكْرٍ كَانَ بَيْنِي وَبَيْنَ امْرَأَتَيَّ فَضَرَبَتْ إِحْدَاهُمَا الْأُخْرَى  

he heard Tawus narrate from Ibn 'Abbas, from 'Umar, may Allah be pleased with him, that he asked about the ruling of the Messenger of Allah concerning that. Hamal bin Malik stood up and said: "I was married to two women, and one of them struck the other with a tent pole and killed her and her fetus. The Prophet ruled that a slave be given (as Diyah) for her fetus and that she be killed (for killing the other woman)." (Using translation from Nasāʾī 4739)   

أَنَّهُ نَشَدَ قَضَاءَ رَسُولِ اللهِ ﷺ فِي ذَلِكَ فَجَاءَ حَمَلُ بْنُ مَالِكِ بْنِ النَّابِغَةِ فَقَالَ كُنْتُ بَيْنَ بَيْتَيْامْرَأَتَيَّ فَضَرَبَتْ إِحْدَاهُمَا الْأُخْرَى بِمِسْطَحٍ فَقَتَلَتْهَا وَجَنِينَهَا فَقَضَى النَّبِيُّ ﷺ فِي جَنِينِهَا بِغُرَّةٍ وَأَنْ تُقْتَلَ بِهَا قُلْتُ لِعَمْرٍو لَا أَخْبَرَنِي عَنْ أَبِيهِ بِكَذَا وَكَذَا قَالَ لَقَدْ شَكَّكْتَنِي  

he asked the people about the ruling of the Prophet ﷺ concerning that - concerning a fetus. Hamal bin Malik bin Nabighah stood up and said: “I was between my two wives and one of them struck the other with a tent-pole, killing her and a fetus. The Messenger of Allah ﷺ ruled that the blood money for the fetus was a slave, and that she would be killed in retaliation.” (Using translation from Ibn Mājah 2641)   

أَنَّ عُمَرَ نَشَدَ النَّاسَ قَضَاءَ رَسُولِ اللَّهِ ﷺ فِي الْجَنِينِ فَقَامَ حَمَلُ بْنُ مَالِكِ بْنِ النَّابِغَةِ فَقَالَ كُنْتُ بَيْنَ امْرَأَتَيْنِ فَضَرَبَتْ إِحْدَاهُمَا الْأُخْرَى بِمِسْطَحٍ «فَقَضَى رَسُولُ اللَّهِ ﷺ فِي جَنِينِهَا بِغُرَّةٍ وَأَنْ تُقْتَلَ بِهَا»  

[Machine] "I was between two women, and one of them struck the other, causing her to die along with her unborn child. The Messenger of Allah ﷺ ruled in this case that a male or female slave should be killed in compensation."  

«كُنْتُ بَيْنَ امْرَأَتَيْنِ فَضَرَبَتْ إِحْدَاهُمَا الْأُخْرَى فَقَتَلَتْهَا وَجَنِينَهَا فَقَضَى رَسُولُ اللَّهِ ﷺ فِيهِ بِغُرَّةٍ عَبْدٍ أَوْ أَمَةٍ وَأَنْ تُقْتَلَ بِهَا»  

he heard Tawus narrate from Ibn 'Abbas, from 'Umar, may Allah be pleased with him, that he asked about the ruling of the Messenger of Allah concerning that. Hamal bin Malik stood up and said: "I was married to two women, and one of them struck the other with a tent pole and killed her and her fetus. The Prophet ruled that a slave be given (as Diyah) for her fetus and that she be killed (for killing the other woman)." (Using translation from Nasāʾī 4739)  

أَنَّهُ نَشَدَ قَضَاءَ النَّبِيِّ ﷺ فِي ذَلِكَ فَقَامَ حَمَلُ بْنُ مَالِكٍ فَقَالَ «كُنْتُ بَيْنَ حُجْرَتَيِ امْرَأَتَيَّ فَضَرَبَتْ إِحْدَاهُمَا الْأُخْرَى بِمِسْطَحٍ فَقَتَلَتْهَا وَجَنِينَهَا فَقَضَى النَّبِيُّ ﷺ فِي جَنِينِهَا بِغُرَّةٍ وَأَنْ تُقْتَلَ بِهَا»  

[Machine] The issue of the Prophet ﷺ in that case was that Hamal ibn Malik ibn al-Nabighah stood and said, "I was between two women, and one of them slapped the other with the palm of her hand, so she killed her and her fetus." So the Messenger of Allah ﷺ made a decision regarding her fetus and said, "It is to be compensated with a slave." And if she is killed, meaning the female killer, then there is doubt about it. 'Amr ibn Dinar doubted it, and what is preserved is that he ruled for her blood money to be paid from the intelligent killer.

Note: The translated passage is provided as accurately as possible, but there may be slight variations in the translation due to the nature of language and cultural differences.  

قَضِيَّةِ النَّبِيِّ ﷺ فِي ذَلِكَ فَقَامَ حَمَلُ بْنُ مَالِكِ بْنِ النَّابِغَةِ فَقَالَ كُنْتُ بَيْنَ امْرَأَتَيْنِ فَضَرَبَتْ إِحْدَاهُمَا الْأُخْرَى بِمِسْطَحٍ فَقَتَلَتْهَا وَجَنِينَهَا فَقَضَى رَسُولُ اللهِ ﷺ فِي جَنِينِهَا بِغُرَّةٍ وَأَنْ تُقْتَلَ كَذَا قَالَ وَإِنْ تُقْتَلَ يَعْنِي الْمَرْأَةَ الْقَاتِلَةَ ثُمَّ شَكَّ فِيهِ عَمْرُو بْنُ دِينَارٍ وَالْمَحْفُوظُ أَنَّهُ قَضَى بِدِيَتِهَا عَلَى عَاقِلَةَ الْقَاتِلَةِ