Bleeding during intercourse on the twentieth day of pregnancy may be due to cervicitis or due to preterm miscarriage. You can take observation, rest, birth control and other methods of treatment to alleviate. 1. Cervicitis: when you are twenty days pregnant, if you have cervicitis and the cervix is eroded, intercourse can cause bleeding on the surface of the cervix, if the bleeding is small and there is no abdominal pain, close observation is sufficient. 2. Pre-eclampsia: Due to the unstable development of the embryo in early pregnancy, coitus may cause uterine contraction, causing bleeding, if the amount is small, no abdominal pain, you can rest in bed, observation, do not have coitus for the time being; if the amount of bleeding is large, accompanied by abdominal pain, you need to be timely treatment of fetal preservation. If a pregnant woman is twenty days pregnant and has uterine bleeding at the same time, it is recommended to consult a doctor in time, under the guidance of the doctor, improve the relevant examination, clarify the cause of the disease, and symptomatic treatment.