What is Subchorionic Hemorrhage in Pregnancy?

What is Subchorionic Hemorrhage in Pregnancy?

A subchorionic hemorrhage is a common finding on ultrasound. Where do they come from? How are they treated? Does a subchorionic bleed predict miscarriage? Learn everything you need to know.

Here is a common scenario. You have an early pregnancy ultrasound and your doctor tells you that there is a collection of blood between the uterine wall and where the pregnancy is implanted. This is called a subchorionic hemorrhage or bleed. What caused it? Can you prevent it or heal it? Does having one mean you're going to have a miscarriage? I will answer all of these important questions.

Early pregnancy ultrasound

Ultrasound is a valuable tool in early pregnancy. Doctors can use ultrasound to identify women who have a non-viable pregnancy or those who might be at greater risk for miscarriage. Sometimes findings on ultrasound, however, can raise more questions than they answer. The finding of a subchorionic bleed is one of those times.

subchorionic hemorrhage ultrasound

Understand how embryo implantation works

When an embryo implants, it actually goes underneath the surface of the uterine lining. The cells of the embryo are divided into those that form the fetus and those that form the placenta. As the placenta starts to form, blood vessels from the mother's uterus, called spiral arteries, start to move into the placenta. Spaces start to form in the placenta and they merge together with other spaces forming channels like a sponge. This is all very normal. It is how the oxygen and nutrients get to the placenta.

How dose a subchorionic bleed form?

Sometimes too much blood accumulates in these channels and it pushes the placenta away from the uterus. If these blood-filled spaces get big enough, they can be seen on ultrasound and we call them a subchorionic hemorrhage. If the blood pushes its way to the edge of the placenta, it can find its way out of the uterus and cause a woman to see vaginal bleeding. Most of the time, these collections of blood will shrink on their own and become so small that you can't see them anymore. This could take anywhere from a few days to a few weeks. In some cases, they may not go away completely and can still be seen months later.

Myths about subchorionic bleeds

Let's dispel a few myths about subchorionic hemorrhage. There is no evidence that having sex or exercising during pregnancy will cause a subchorionic bleed. There is no evidence that bed rest will make a subchorionic bleed go away more quickly. There is no evidence that eating or not eating certain foods will make a subchorionic bleed resolve more quickly. There is also no benefit for increasing fluids. There is no homeopathic voodoo, spells or remedies or any supplements that will make a subchorionic bleed go away any faster. Don't throw away your money on any of these scams - they do not work! The question I get asked a lot is this:

Does a subchorionic hemorrhage predict miscarriage?

The quick answer is "maybe". In women who are having vaginal bleeding, ultrasound can find a subchorionic bleed about 10% of the time. However, they are also found commonly in routine ultrasounds for women who are having no complications. In the 40 years since subchorionic bleeds were first identified, it is still unclear whether they are more common in women who miscarry versus in women that do not. There have been some studies that have tried to identify if women who are identified with a subchorionic bleed have a higher risk for miscarriage.

These studies are difficult to interpret. For example, when looking at the size of the blood collection on ultrasound, different studies used different methods to measure them. Some studies just measured the length of the blood collection, others tried to estimate the size relative to the size of the gestational sac. These differences make it very difficult to compare these studies. Other studies have also tried to look at the location of the bleed, how far along the pregnancy was when the hemorrhage was diagnosed, how old the mother was and whether a woman noticed vaginal bleeding or not. To date there is no conclusive evidence that any of these characteristics predict a greater likelihood for miscarriage.

Bottom line

Subchorionic bleeds are a common finding in early pregnancy. Although this can be a stressful scary finding, most of the time they are going to resolve on their own. There is no evidence that anything you did or didn't do was the cause of this collection of blood. There is no treatment for a subchorionic bleed. You can continue your normal activities and please please don't get conned into buying any treatment or supplement it is a waste of your time and money.