A small amount of blood accumulation in the uterine cavity occurs in early pregnancy and is usually gradually absorbed. However, there are individual differences in the exact timing, and some pregnant women may gradually subside in mid to late pregnancy. When a woman is pregnant with a normal uterine cavity with a developing gestational sac and a pulsating fetal heart, a small amount of blood accumulation in the uterine cavity around the gestational sac is still considered to be a preterm abortion and can be treated with fetal preservation medication until it subsides naturally. However, the exact time of elimination of the blood accumulation varies from person to person, most of them are about half to two months, and some pregnant women may even reach four months. If the accumulation of blood in the uterine cavity is not eliminated for a long time, it may cause frequent contractions and risk of miscarriage. Therefore, once a pregnant woman has accumulated blood in the uterine cavity, it is recommended to actively carry out fetal preservation treatment. The amount and duration of medication depends on the amount of progesterone and the amount of accumulated blood in the uterine cavity. During this period, pregnant women should pay attention to bed rest and avoid overexertion. When the amount of bleeding is small, no special treatment is usually needed. However, for patients with large amount of blood accumulation in the uterine cavity, they should be actively hospitalized for fetal preservation treatment.