placental problems
Here are some answers to your questions. First we need to clarify the translation of שליה נעוצה because in English there are several variations, according to severity. Most cases are just when the placenta doesn't separate from the wall of the uterus (adherent placenta) , and needs to be manually separated by putting in the hand in the uterus when the woman is under general anesthesia in the operating room. They call it גרידה but it is really a manual removal of placenta, with no instruments. Then there is a placenta accreta of varying degrees, where the placental cells go into the wall of the uterus, sometimes just the inner lining, sometimes into the muscle layer and sometimes include the entire depth of the uterine wall. These are all problematic and it is very hard to separate and can lead to serious blood loss and even to hysterectomy. This can be a complication of many abortions, or surgery in the uterus or after a Cesarian when the placenta implants in the scar. It is not usually diagnosed until after the birth and the problems with the placenta begin. It is possible with ultrasound to see if the placenta is implanted in the scar area. It is possible to totally birth naturally, but then you could have major problems with the placenta and would need a hospital. If someone had a placenta accreta in the past, this would not be recommended to birth at home for the next birth. I never heard there was a connection with having lots of babies, or multiple births. It certainly can happen with no apparant reason, but this is very rare.