I have heard that it is haram for a woman to tie her tubes. My sister has 4 children and is now 40. Is it haram for her to tie her tubes? And also, I have been advised that due to having blood clots in my lungs and now medicated for life that if I’m to fall pregnant again I could die and will need to abort my unborn child. In this case is tying the Fallopian tubes permissible?