A subchorionic hematoma, sometimes called a subchorionic hemorrhage (SCH), is a pocket of blood that forms between the placenta and the uterus. Some doctors describe it as a clot and others describe it as a separation or tear.
It is not completely known what causes the hemorrhaging, but doctors believe the egg can possibly tear the uterus from the placenta during implantation.
A woman will not know she has one until her first ultrasound. On the screen, they appear as small oblong shaped black masses usually much smaller than the gestational sack. Don’t fret just yet if your doctor says they’ve discovered one — they are the most common gestational abnormality among live embryos. As many as one in four women have had one at some point in their pregnancy, and many doctors don’t even bother telling their patients especially if they are small.
Many experience bleeding in the first trimester and not necessarily because they are having a miscarriage. SCHs will often “bleed out” which can be quite alarming for a newly pregnant mother-to-be. There is nothing really a woman can do at this point other than to wait it out and rest assured that her fetus is in very little danger from the bleed itself. Some doctors recommend taking it easy and avoiding sex and tampons during this time.
Some SCHs do not cause bleeding at all. This was the case for me. I was diagnosed with a small clot during my routine seven-week ultrasound. I worried needlessly over it and was terrified of bleeding out of fear of having a miscarriage. I read that some women’s bodies just reabsorb the clot and that is that. It must have happened that way for me, because by my next ultrasound at 19 weeks, the hematoma was nowhere to be seen and I found I had a healthy and active little girl in there!
Only 1-3 percent of SCHs will cause a miscarriage. These are often ones that are considered large, tearing at least 30-40 percent of the placenta from the uterus. Unfortunately, there is nothing much either you or your doctor can do from prevent the miscarriage at this point.
Even though the name itself sounds frightening enough as it is, if your doctor tells you he has found a subchorionic hematoma, ask him how big it is and if there is any reason for concern. Chances are, there is nothing to worry about. I wish I had known the statistics before frantically searching the Internet only to come across the worst possible scenarios. Trust your doctor and your body — they know what they are doing.