Bleeding during pregnancy is not normal , always a worry, but not always bad. The bleeding could be from the uterine vessels, or your cervix becoming aged or ripening. An ultrasound don't always show up blood so a doctor visit and examination is most necessary to determine the problem.
Not much can be done for a subchorionic bleed or hemorrhage. Generally the woman is put on bed and pelvic rest (no sex, no lifting heavy items) until it resolves itself. It can be a dangerous complication in pregnancy so a doctor's orders should be followed to the letter.
Subchorionic bleed treatment consists of observation by an obstetrician, avoidance of heavy lifting, and possible avoidance of intercourse for the pregnancy remainder. Some physicians will prescribe a blood thinner like Coumadin or Lovenox.
Most common treatment for "subchorionic bleed/hematoma/hemorrhage"
(between placenta & uterus) is "bed rest";
Alternatively, certain hormones could be prescribed,
or Minimally-invasive surgery to:
cauterize, break/dissolve clot, & remove.
The percentage of it happened in pregnancy is quite small but it can lead to complicated pregnancy. Regular monitoring of the pregnancy by ultrasound examination is required.
Subchorionic bleed is a bleeding between the placenta and uterus and affect about 1% of total pregnancy. Ultrasound should be done regularly to monitor the progress of the pregnancy.