Blood sinusoids are a type of capillary, mainly located in endocrine glands such as the dry skin bone marrow, which is the area where blood enters the tissue interstices from blood vessels. Because the human body’s true cavity is not particularly well developed, the microvasculature and venous cavities in the body become larger and are not surrounded by blood vessels, forming unorganized and irregular gaps through which blood flows in the body to form blood sinuses. It is possible to develop placental blood sinuses during pregnancy, mainly due to the rupture of blood vessels between the endometrium and the mucosal placenta, which accumulates over time. It usually has little effect on the pregnant woman, but tends to produce postpartum bleeding. If the situation is more serious, there may be placental abruption and premature labor, the blood sinus should pay more attention to rest and less strenuous exercise. If the blood sinus is more serious, you should go to the hospital in a timely manner, and go to the hospital for regular review.