When a patient has signs of miscarriage in the first month of pregnancy, the following clinical manifestations may occur: First, the patient’s early pregnancy reaction may suddenly decrease or disappear. The early pregnancy reaction is mainly due to the increase of blood HCG, progesterone and estrogen prolactin levels after pregnancy. The increase of these hormone levels can cause early pregnancy reaction such as nausea, vomiting, weakness, drowsiness and breast swelling and pain. When there are signs of miscarriage, the embryonic activity will be reduced or the embryo will die. In this case, the hormone level in the patient’s body will drop rapidly, so these early pregnancy reactions will be significantly reduced or disappear suddenly. Second, the patient may have abdominal pain and bleeding. After the embryo activity decreases or dies, it will be separated from the normal uterine wall and will stimulate the uterus to contract, so the patient will have abdominal pain and bleeding.