What is the ruling on unintentional abortion?

If the miscarriage was unintentional, there is no sin in it, as Allah says: "And there is no blame upon you for that in which you have erred," and the Prophet, peace and blessings be upon him, said: "Error and forgetfulness have been lifted from my Ummah."

If the miscarriage was caused intentionally and occurred after forty days, then a ghurrah (one-tenth of the mother's blood money) is due from the one who caused it or the ‘aqilah (male relatives on the father's side). The one who caused it does not inherit from it. Additionally, an expiation (kaffarah) is obligatory according to the Shafi'i and Hanbali schools (emancipating a believing slave, and if not found, then fasting for two consecutive months), and recommended according to the Maliki and Hanafi schools.