Abu Hurairah (RAA) narrated "Two woman of the tribe of Hudhail fought with each other and one of them threw a stone at the other. In this way she killed the woman and what was in her womb (as she was pregnant). Their dispute was presented to the Prophet (ﷺ) who ordained that the Diyah (blood money) of the unborn child, is a male or a female slave of the best quality. He also decided that the Diyah of the woman is to be paid by her relatives (the one who killed) on her father's side. The Messenger of Allah (ﷺ) also ordained that her inheritance (of the woman who killed as she died later) be for her sons and husband (and not for her relatives who had to pay the Diyah). Hamal bin An-Nabighah Al-Hudhaili then said, 'O Messenger of Allah! Why should I pay the Diyah for one who neither drank nor ate nor spoke, nor cried (i.e. the dead fetus), such a creature is not entitled to blood money.' The Messenger of Allah (ﷺ) then said, "This man is one of the brothers of the soothsayers," on account of the rhymed speech which he used, concerning the dead fetus.
English reference: Book 9, Hadith 1209
Arabic reference: Book 9, Hadith 1179