Before the days of sophisticated medical imaging, countless women sailed through seemingly perfect pregnancies, producing perfect little people, without ever knowing they had complications like a uterine blood clot. But with the advent of pregnancy ultrasounds, you're now much more likely to find out (and worry) about these types of occurences. A blood clot in the uterus isn't usually a major cause for concern though. Here's what to expect after one is detected. 

What are uterine blood clots?

Most of the blood clots that turn up on sonograms during the first trimester are what doctors call subchorionic hematomas. In plain English, that means a blood clot that's situated between the wall of your uterus and your baby's gestational sac (or chorionic membrane).

Uterine blood clots are no different from those that occur anywhere else in the body: They form from coagulated blood cells and proteins.

What causes a blood clot in the uterus?

If you have a uterine blood clot, you must have been bleeding in your uterus at some point, which is much less ominous than it sounds. Sometimes, they cause noticeable vaginal spotting or bleeding, which is quite common during early pregnancy. 

But what caused the bleeding? It’s hard to be certain. It may have been a ruptured blood vessel. Or the hematoma may have slightly separated the placenta from the uterine wall — a condition called a placental abruption, which, with early diagnosis, your doctor should be able to reduce the risks for you and your baby.

What does a uterine blood clot mean for my pregnancy?

Over time, the clot may be reabsorbed into the uterus, or it may just loiter around harmlessly until your baby is born. On your follow-up visit, your doctor will likely perform another ultrasound to find out. As long as the pregnancy is progressing nicely, you’re at no higher risk of complications.

Hearing that you have a blood clot during pregnancy can feel frightening. The good news is that first trimester blood clots (or subchorionic hematoma) are rarely associated with either miscarriages or problems later in the pregnancy. In the meantime, to be on the safe side, heed your doctor’s advice and take it easy.

Your doctor may limit exercise and put your pelvis off-limits to vaginal exams (and, sadly, pregnancy sex). So get as much bed rest as possible — and consider it a well-deserved breather. Brewing a baby is an exhausting business! Most importantly, put the worrying on the back burner.