The cause of miscarriage can be determined by checking the chromosomes of the gestational sac, in addition to the type of miscarriage by examining the mother. The causes of miscarriage include chromosomal abnormalities of the embryo, uterine abnormalities of the mother and so on. 1. Embryonic chromosome abnormality: it is the more common cause of early miscarriage, accounting for about 50%~60% of the causes of early miscarriage, therefore, if you need to find out the cause of miscarriage, you can keep the gestational sac for chromosome number and structure examination. 2. Maternal uterine abnormalities: including longitudinal uterus, uterine adhesions, etc., such abortion is due to the mother’s uterine cavity morphology is abnormal, affecting the development and growth of the embryo, resulting in miscarriage, through the hysteroscopy can be clearly diagnosed. There are many other causes of miscarriage, including maternal luteal insufficiency, smoking, and environmental factors, in addition to those mentioned above. Patients who have miscarriages can be seen in the prenatal clinic to find out the cause of the miscarriage and to avoid a similar situation in the next pregnancy.