Does expiation become obligatory for one who caused the death of her infant daughter by suffocation after the latter turned over onto her face while sleeping, wrapped in a swaddling cloth?

The expiation for killing and blood money are obligatory for whoever kills another by mistake, whether directly or by causation. Direct killing unequivocally necessitates guarantee (dhaman), whereas killing by causation does not necessitate guarantee and expiation unless the causer was transgressing (muta'addiyan) or negligent (mufarrittan). Negligence is the ترك ما يجب من الحفظ (failure to do what is required for preservation), and transgression is the فعل ما لا يجوز من التصرفات (performing actions that are not permissible). In the mentioned case, the mother is not required to offer expiation due to the absence of any transgression or negligence on her part.