She had an operation on her uterus
Question

                If a woman has an operation on her uterus and bleeds as a result, is that blood regarded as menses?.
Praise be to Allah.
    A woman may experience something that causes her to bleed 
    from her vagina, such as an operation on the uterus or close to it. This 
    falls into two categories: 

    1 – If she knows that it is not possible for her to 
    menstruate after the surgery, such as if she has an operation to remove the 
    uterus altogether (hysterectomy) or blocking it so that no blood can come 
    from it. This woman does not come under the rulings on istihaadah 
    (non-menstrual vaginal bleeding); rather she comes under the rulings on one 
    who sees some yellowish or brownish discharge or some wetness after her 
    period ends. So she should not stop praying and fasting, or refuse to let 
    her husband have intercourse with her, and she does not have to do ghusl in 
    this case. But when she wants to pray she should wash the blood from herself 
    and put a piece of cloth or something similar over her private part to 
    prevent the blood coming out, then she should do wudoo’ and pray. She should 
    only do wudoo’ after the time for the prayer has begun, if there is a 
    specific time for the prayer such as the five daily prayers, or when she 
    wants to offer a naafil prayer. 

    2 – If she knows that there is no reason why she should not 
    menstruate after the operation and it is possible that she may menstruate. 
    This comes under the ruling of istihaadah and is indicated by the words of 
    the Prophet  (peace and blessings of Allaah be upon him) to Faatimah 
    bint Hubaysh: “That is a vein and is not menses. When the time of menses 
    comes, then stop praying.” The words “when the time of menses comes” 
    indicate that the ruling on istihaadah may apply to one who has a period 
    that comes and goes. If a woman does not have a period then her bleeding is 
    regarded as coming from a vein in all cases. End quote.