Brown discharge is composed of a small amount of blood as well as normal vaginal leucorrhea. The presence of brown vaginal discharge in early pregnancy needs to be taken seriously by pregnant women. Brown vaginal discharge in early pregnancy may be a sign of preterm miscarriage. A small amount of vaginal bleeding may occur prior to the miscarriage as the fetal sac gradually breaks away from the uterine muscle layer. However, the presence of brown vaginal discharge does not necessarily mean that miscarriage will occur. Secondly, a low level of progesterone in a pregnant woman’s body can also cause brown vaginal discharge. Therefore, pregnant women need to monitor their progesterone levels regularly and provide progesterone supplementation if necessary. In addition, vaginal discharge may also be caused by the high activity of the pregnant woman. Regardless of the factors, in order to avoid adverse pregnancy outcomes, pregnant women are advised to observe the amount of vaginal bleeding when it occurs and to pay attention to the presence of lower abdominal pain. If the amount of bleeding gradually increases, it is recommended that the patient immediately consult a local hospital to identify the cause of the vaginal bleeding and then take symptomatic treatment according to the cause and, if necessary, hospitalization for fetal preservation. As mentioned above, brown vaginal discharge is an abnormal phenomenon and patients are advised to seek medical attention.