Light brown discharge on the 42nd day of pregnancy is mainly seen in the following clinical possibilities: First, when there is a pre-miscarriage or when the embryo stops developing, vaginal bleeding can occur, and it may be accompanied by a drop in the abdomen, pain and discomfort. Blood HCG and progesterone can be checked to determine the activity of the embryo and help to diagnose. Second, the patient has the possibility of ectopic pregnancy. If the patient has vaginal bleeding after 42 days of pregnancy without ultrasound to determine intrauterine pregnancy, ectopic pregnancy should be highly suspected. It is necessary to clarify the diagnosis by dynamically observing the changes in blood HCG, progesterone and color ultrasound. Third, there may be bleeding caused by vaginal or cervical lesions, such as cervical polyps, intraepithelial neoplasia of the cervix or inflammation of the vagina.