Hysterectomy
Question :

A woman undertook the operation of hysterectomy - the removal of the womb. Afer that, she started to have some vaginal bleeding because of the wounds inside. Is it permissible for her to fast?

Answer :

Yes, she is permitted to fast. The release of such a blood from the womb is recognized as Istihadha. It is of three types as mentioned in the treaties of the practical religious laws.

Istihadha
Question :

I got finished my menstrual period a week ago. But now I have blood spotting, and it's not the regular form of bleeding. Can I prayer this this state?

Answer :

If this blood is from a wound, then the area must be purified (made tahir) before offering prayers. If it is from the womb then it is not considered as period (haydh), but it is istihādha, and the rulings of istihādha apply then.