Sometimes when you have a scan in early pregnancy an area of bleed can be seen next to the pregnancy sac in the womb. The medical term for it is a “subchorionic haematoma”. It can be present without any vaginal bleeding. Different studies have reported varying rates of this of this being found in between 3-11% of pregnancies. It often causes worry about what it means for the pregnancy.
The presence of this scan finding may slightly increase the risk of pregnancy loss. But the great majority of pregnancies where a baby with a heartbeat is seen will continue. A recent study found that the pregnancy was 80% likely to continue if the subchorionic haematoma was seen before 7 weeks and 96-97% likely after 8 weeks. The overall likelihood of pregnancies continuing was 88%. To put this into context the background risk of early pregnancy loss is 11% age 25-29, 12% at age 30-34 and 15% at 35-39. (RCOG). So overall the outcome for subchorionic haematomas where a viable baby is seen is very good.
The authors of this study looked at various ways of predicting the outcome. Measuring the size of the bleed area in three dimensions was not found to be helpful in predicting the outcome but assessing the size as a fraction of the gestation sac size was.
It has been found that taking aspirin increases the risk of these areas of bleed fourfold so it is important to avoid this if possible in the first trimester. If your doctor has recommended aspirin for a medical condition a discussion of the risks vs benefits should be had.