If a pregnant woman is in good condition after ultrasound examination and still has brown blood and the amount of blood is not much, it is mostly due to the blood that has accumulated in the uterine cavity, so the blood is darker in color and appears brown. In some cases, when a pregnant woman has a mild attack such as pre-eclampsia or miscarriage, although the embryo is developing normally under ultrasound examination, there is still vaginal bleeding due to a significant decrease in progesterone in the body. In some cases, when women have severe cervicitis, vaginitis, or cervical polyps, the bleeding from these inflammatory sites may come out of the vagina and may appear brown because the amount of bleeding is relatively small and mixed with the discharge. Therefore, for pregnant women with brown discharge, it is necessary to identify the cause of the problem and treat it according to the cause.