I am an obstetrician in Melbourne Australia. I have quite a few charedi patients (ken yirbu!). A small number of them have had multiple caesarean sections. They can be hard to persuade that they have fulfilled pru u'rvu.
With increasing numbers of Caesarean sections comes increasing risks-
The risks are as follows:
Placenta accreta occurs when the placenta binds to the previous uterine scar and does not separate after the birth. It has been reported that placenta accreta increases with each caesarean section birth for example:
0.24 per cent for the first birth;
0.31 per cent for the second;
0.57 per cent, for the third;
2.1 per cent for the fourth;
2.3 per cent for the fifth and
6.7 per cent for the sixth birth.
The potential outcomes are:
A review including 109 cases of placenta percreta reported the following types and frequencies of complications: transfusion of over 10 units (44 cases), infection (31 cases), perinatal death (10 cases), maternal death (8 cases), ureteral ligation or fistula formation (5 cases each), and spontaneous uterine rupture (3 cases).
Certainly a condition that has a 8% chance of death and a 40% chance of needing more than 10 units of blood is a real saken nefashot!
The risk is permanent. Most nonJewish obstetricians would advise that women have no more than 3 or at the most 4 Caesarean sections. I would think that once the risk of the condition is over 5%, so that the risk of death with pregnancy is about 1/250, this should be a significant enough risk to advise that further pregnancy is not only inadvisable, but forbidden?
Are there previous questions along these lines?
a. In Israel, in cities with a high percentage of Haredi patients, the doctors usually provide the couple precise data regarding the risks and complications of repeating pregnancies and childbirths.
Haredi couples usually consult with their Poskim and present this information to them. After the deliberation, they bring their decision to the doctor
b. From a Halachic perspective – except in cases where the risk is very high, one cannot forbid a women who wishes to bear a child even if such childbirth carries some risk.