Sahih Bukhari Volume 9, Book 83, Hadith Number 41.

Narrated By Abu Huraira : Two women from the tribe of Hudhail (fought with each other) and one of them threw (a stone at) the other, causing her to have a miscarriage and Allah’s Apostle gave his verdict that the killer (of the fetus) should give a male or female slave (as a Diya).