When black blood appears after pregnancy, there are two possibilities to consider: 1) most of them have the possibility of pre-eclampsia miscarriage; 2) the embryo is suspected to have stopped developing. Most of the pre-eclampsia miscarriages are due to the low progesterone in the pregnant woman’s body, the fetus is not very solidly embedded inside the uterus, so the embryonic villi are easily separated from the uterine wall, the bleeding in this case is not a lot, and it is dark red, some people may have the clinical manifestation of small stomach swelling and pain. In addition to black blood, the patient will also experience the disappearance of the early pregnancy reaction, that is, if there was nausea and vomiting before, the symptoms of nausea and vomiting will suddenly disappear and the uterus will no longer increase in size, but will shrink instead.