Usually, a subchorionic bleed does not affect the pregnancy or the fetus. It usually dissipates on its own within a few weeks. It is quite rare for there to be hemorrhage to such extent that the hemoglobin drops so low as to compromise the fetus. Certainly, your hemoglobin must be monitored and the blood replaced to maintain a good level of hemoglobin. In the vast majority of cases, a subcnorionic hematoma will not cause any effect on the baby. If there is heavy bleeding, call your doctor immediately.
i had a subchorionic hemorhage when i was pregnant with my son and still went on to deliver a healthy baby and i also had one with this one and i am now 20 wks