Is it permissible for a man and a woman to undergo a "ligation" procedure to prevent further childbirth, if he has 7 children and she has 5 children, and their financial and living conditions do not allow for more children?

It is not permissible to perform a complete sterilization, except in cases of extreme necessity, such as fear of the woman's demise. However, it is permissible to use a temporary method to postpone conception, if both spouses agree upon it for a valid reason.