In this chapter concerning the laws of personal injuries, the word "pay" or "payment" appears 8 times. Besides the eye-for-eye justice, some compensation can be demanded or offered.
Exodus 21:28 If a bull gores a man or woman to death, ...
However, if payment is demanded, the owner may redeem his life by the payment of whatever is demanded.
Ellicott's Commentary for English Readers
(30) Whatsoever is laid upon him.--Primarily, by the aggrieved relatives; but in the case of an exorbitant demand there was, no doubt, an appeal to the judges, who would then fix the amount.
In this case of a bull killing a person, the death penalty is extremely unlikely.
Verse 30. - If there be a fine laid upon him. There can scarcely have been any circumstances under which the penalty of death would have been enforced. No neglect could bring the crime into the category of murder. It is assumed, therefore, that practically the penalty would be a fine, proportioned no doubt to the value of the life taken.
I'd suggest that to the Israelites in that culture, the accidental cause of death to an unborn would be treated similarly by monetary compensation.