Subchronic Bleeding: What You Need to Know

The word "hemorrhage" sounds scary — and all the more so when it refers to a condition that can occur during pregnancy.

A subchorionic hemorrhage (SCH) is also referred to as subchorionic hematoma or bleeding. It's one of the leading causes of vaginal bleeding during early pregnancy.

The good news is that if a subchorionic hematoma occurs, it usually doesn't mean the pregnancy is in danger. Research has found no correlation between the presence of SCH alone and adverse pregnancy outcomes.

Here's what experts say you should know.

What is subchorionic hemorrhage?

A subchorionic hemorrhage (SCH) occurs when blood forms between the amniotic sac and the outer layer of the uterine wall, which is called the chorion or chorionic membrane. "A hemorrhage is formed when there's a little separation between the placental wall and that outer layer," says Sara Holt, CNM, MS, a certified nurse midwife at Byenveni Baby in Portland, Oregon.

SCH is one of the most common causes of vaginal bleeding in early pregnancy. Its rate of occurrence is between 11% and 12.5% in patients who are between 10 and 20 weeks pregnant. Other estimates put the rate as high as 39.5%.

"SCH is quite common, and many likely go unrecognized because they resolve before the woman has an ultrasound," says Caitlin Dunne, M.D., FRCSC, a reproductive endocrinologist and fertility specialist in Vancouver.

What causes subchorionic hemorrhage?

In most cases, there is no clear cause of an SCH. But some possible causes may include the following:

Implantation trauma

"A lot of times, a subchorionic hemorrhage is related to how that whole pregnancy is implanting on the side of the uterus and developing," Holt says. "So if there's an area of less robust, less healthy tissue and your pregnancy attaches to that, you would be more likely to see something like that."

Placental or uterine abnormalities

Abnormalities of the placenta or uterus may also cause SCH to develop.

Other medical conditions

Past pelvic infections or reproductive issues may factor into the development of SCH. "They do seem to be more common in women with a history of recurrent miscarriage, uterine malformations and infection," Dunne says.

What are the symptoms of subchorionic hemorrhage?

Vaginal bleeding and spotting are the most common symptoms, though this doesn't occur in every instance. Although uncommon, some people with SCH may experience light cramping or abdominal pain.

"In some cases, there may be no symptoms, and the condition is only discovered during routine prenatal imaging," says Rakhee Patel, M.D., FACOG, an OB-GYN at Pinewood Family Care Co. in New Jersey.

Dunne adds, "Some women do not know they have SCH until a routine ultrasound. It really depends on where the SCH is located. If it is walled off by the gestational sac, then blood may not leak out, and you won't notice spotting."

Light bleeding or spotting during early pregnancy is widespread and can be attributed to a variety of causes. Even so, let your doctor know if you have any bleeding or spotting.

"It's crucial to seek medical treatment if you experience any bleeding during pregnancy to rule out more serious issues," Patel says.

What are the risk factors?

"While SCH cannot always be prevented, regular prenatal care can help manage the condition and monitor the health of both the mother and the fetus," Patel says.

Some factors may increase the likelihood of developing SCH.

History of miscarriage

Prior miscarriage, especially if a D&C was administered, may increase the risk of SCH, Holt says. "After a miscarriage or termination, there's always a risk of scar tissue in the uterus," she says. "Things that would cause inflammation or scar tissue, you would be more likely to have implantation difficulty."

Other medical conditions

Underlying health conditions may increase the risk of SCH. "Certain conditions, like high blood pressure, autoimmune disorders, or clotting disorders, may increase the risk," says Mickey S. Coffler, M.D., FACOG, a board-certified reproductive endocrinologist at HRC Fertility in California

Some medications associated with some health conditions may also increase the risk. "Some studies have suggested that taking anticoagulants and/or aspirin can also increase the risk of SCH," Dunne says.

What are possible complications?

While complications are not automatic when a pregnant person experiences SCH, they can happen. However, it's important to note that research has found no statistically significant differences between people with SCH and those without SCH.

Here are some potential pregnancy complications:

Miscarriage

SCH alone doesn't necessarily indicate impending pregnancy loss. However, the risk of miscarriage increases when SCH is accompanied by other symptoms — mainly heavier bleeding and abdominal pain or cramping.

Placental abruption

While rare, another possible complication from SCH is placental abruption, when the placenta either partially or fully detaches from the wall of the uterus before childbirth.

Gestational hypertension

"There have been some studies that say for people that have a subchorionic hemorrhage, there can be a risk of pregnancy-induced hypertension later on," Holt says. High blood pressure during pregnancy is one of the more common complications of SCH.

Preterm labour or birth

Preterm labour is not a common complication, but it can occur. Some research found if preterm birth does happen in people with SCH, it's most often between 34 and 37 weeks gestation.

"Most SCH is not anyone's fault or the result of any wrongdoing," Dunne says. "They happen, and most pregnancies do just fine."

How to manage and treat subchorionic hemorrhage?

Usually, SCH requires only monitoring, not medical intervention. "Generally, a SCH is self-limited, and it will resolve on its own, just like a bruise resolves," Dunne says.

Ultrasounds

"Regular ultrasounds will be performed to assess the size of the hemorrhage and ensure fetal well-being," Coffler says.

Rest

If you have SCH before 20 weeks, your doctor might recommend rest. This could include bed rest, avoiding lifting heavy objects or participating in strenuous activity.

Your physician may also recommend pelvic rest or no sex until the SCH resolves.

Medication or other intervention

Medication, hospitalization or other medical intervention may be recommended in more severe cases of SCH.

"There is no guaranteed way to prevent SCH, but maintaining a healthy lifestyle with good nutrition and regular prenatal care is important for all pregnancies," Coffler says. "Early detection and appropriate management can minimize potential complications."

Experts

• Sara Holt, CNM, MS, a certified nurse midwife at Byenveni Baby in Portland, Oregon
• Caitlin Dunne, M.D., FRCSC, a reproductive endocrinologist and fertility specialist in Vancouver
• Rakhee Patel, M.D., FACOG, an OB-GYN at Pinewood Family Care Co. in New Jersey
• Mickey S. Coffler, M.D., FACOG, a board-certified reproductive endocrinologist at HRC Fertility in California