Is blood money obligatory for one who aborts a fetus due to dangerous therapeutic reasons, and is it permissible to pay it in installments?

Aborting a fetus is impermissible unless there is a necessity, such as its continued presence posing a danger to the mother's life. In such a case, if trustworthy doctors determine this, then abortion is permissible, and neither blood money (diyya) nor expiation (kaffarah) is required; this is because the fundamental principle is the absence of liability for an authorized action.