Miscarriage in the third trimester is often caused by the following factors: 1. the influence of external adverse factors, such as exposure to toxic and harmful chemicals, like organic mercury, lead, cadmium, smoking, which causes miscarriage. 2. caused by the pregnant woman’s own suffering from a certain disease, such as high fever during pregnancy, which causes uterine contractions and leads to miscarriage, bacterial infection, which stops the development of the embryo, which can also 3. if a pregnant woman suffers from chronic nephritis or hypertension, miscarriage may also occur. 4. due to genital development malformations, such as bicornuate uterus, or longitudinal septum, uterus, uterine dysplasia, or due to uterine fibroids may cause the embryo to stop developing and cause miscarriage. 5. endocrine disorders, such as luteal insufficiency, may also lead to the possibility of miscarriage.