What is the cause of abortion three months pregnant?

The most common cause of miscarriage after three months of pregnancy is a genetic abnormality in the fertilized egg. It can also be caused by exposure to chemicals, drugs or uterine abnormalities during pregnancy. Advice: Women need to go to the hospital for a B-ultrasound to determine if there is residue in the uterus. If there is residue, they need to be treated with curettage.