Umar bin Khattab reported,

I witnessed the Messenger of Allah ﷺ give judgment in such a case, ruling that compensation was to be a slave, male or female.Umar said, "Bring me someone who will testify along with you."So he brought Muhammad bin Maslama. Harun added, "and he testified for him," meaning concerning a man who struck his wife's belly.Abu Dawud said, I was told on the authority of Abu Ubayd that this is called imlas because the woman lets the child slip out before the time of delivery, and likewise anything that slips from the hand or from anywhere else is said to have slipped away.

Abu Dawud 4571

Sahih

حدثنا موسى بن إسمعيل حدثنا وهيب عن هشام عن أبيه عن المغيرة عن عمر بمعناه

أبو داود 4571صحيح
Contents
Reference
Commentary
Ayat
Collection
Sunan Abu Dawud
Book
Blood money
Chapter
Compensation for the fetus
Numbering
Darussalam 4571
Abu Dawud 4571