There are many reasons why the first menstrual flow is low and black after abortion, which may be related to the hormone level or caused by damage to the endometrium after abortion, such as endocrine disorders, endometrial damage and uterine cavity adhesions, etc., which need to be dealt with according to the specific situation. 1. Endocrine disorders: After abortion, the gonadal axis has not fully recovered and the hormones in the body have not yet returned to the previous level, resulting in a decrease in menstrual flow. If there is no other discomfort, it can be observed for 1-2 weeks, if it continues to be abnormal, endocrine-related examination is needed; 2, endometrial damage: abortion has a certain degree of damage to the endometrium, resulting in thinning of the endometrium, resulting in less menstrual volume, and the color will become darker or darker after neutralization with the vaginal acid. The color will become darker or darker after neutralization with vaginal acid. It is recommended to go to the hospital in time and take hormonal medication under the guidance of the doctor to promote endometrial repair; 3. Cervical canal or cavity adhesions: If the recovery is not good after abortion, cervical canal or cavity adhesions may occur. If the adhesions are relatively mild, there are usually no obvious clinical symptoms; if the situation is more serious, there may be a low volume of black menstruation with abdominal pain symptoms. It is recommended to go to the hospital early for medication or surgery.