You should be reaching the time when the incidence of pregnancy loss falls considerably. Bleeding, as you already can see, does not mean imminent miscarriage, and as long as the ultrasound shows appropriate fetal and placental maturation, I would try not to worry.
Blood does accumulate within the uterus because of the further development of the mucus plug. There would be no problems for the baby unless the bleeding is rapid or extensive, distending the uterus or forcing the blood into the uterine muscle. This might cause preterm labor and would certainly compromise the blood flow to the baby.
If you are Rh negative, make sure you discuss RhoGAM with your provider. Also, you should note the position of the placenta with each ultrasound to make sure it is migrating up and out of the way of the cervix. Ask the ultrasound technician to locate the placenta and be aware of any accumulation of blood near it or under it as in the case of an abruption. An abruption is like a clot and if large enough could interfere with blood flow.
I'm sure you will be followed with serial ultrasounds and if the baby is appropriate for gestational age, you should feel reassured.
I wish for you a term pregnancy and a healthy baby.