When a woman is 50 days pregnant, if there is accumulation of blood in the uterine cavity, it is a more serious situation, which may be the cause of pre-miscarriage, embryo abortion and so on. Accumulation of blood in the uterine cavity indicates that the development of the fetus in the uterus is abnormal, such as fetal chromosomal abnormalities or external stimuli, resulting in abnormal bleeding in the uterus. If the development of the fetus has not stopped, it means that there is a pre-eclampsia, which requires timely preservation of the fetus. If the fetus has already died, it is necessary to terminate the pregnancy in time to prevent intrauterine infection. If blood accumulates in the uterine cavity on the 50th day of pregnancy, you need to go to the hospital in time, and under the guidance of the doctor to carry out the appropriate examinations and treatments, in order to prevent miscarriage and other conditions.