It was narrated from Ibn ‘Abbas (رضي الله عنه) that

'Umar (رضي الله عنه) witnessed the Prophet (ﷺ)'s verdict concerning that. Hamal bin Malik bin an-Nabighah came and said: I was between two women and one of them struck the other with a tent-pole, killing her and her foetus. The Messenger of Allah (ﷺ) ruled that a male or female slave be given (as diyah) for her foetus and that she should be executed.