What is a subchorionic bleed?
It sounds scary, but it's not usually serious. A subchorionic bleed (or hematoma) happens when blood leaks out and collects between the uterine wall and the chorion, the membrane around your growing baby. The chorion also makes up part of the placenta, and subchorionic bleeds often appear near the placenta. They show up in about 2 percent of pregnancies.
What are the symptoms of a subchorionic bleed?
There may be no symptoms, so you may find out you have a hematoma if your doctor spots it on a routine ultrasound. In other cases, you might see some spotting or vaginal bleeding. Vaginal spotting in pregnancy is quite common, and most of the time it's nothing to worry about, but let your caregiver know about it. An ultrasound will show if a chorionic bleed is the cause.
Is a subchorionic bleed serious?
Not usually. Early in pregnancy, when they're most common, these bleeds are more likely to stay small and go away on their own. A large hematoma – one that's more than half the size of the amniotic sac around the baby – may increase your risk for miscarriage, so your practitioner will want to monitor it. Your doctor will also keep a close eye on a hematoma that develops toward the end of the first trimester or later, as it may raise your risk of miscarriage, placental abruption, preterm labor, or stillbirth.
What causes a subchorionic hematoma?
Experts aren't sure why subchorionic bleeds happen. They're more common among women who've had in vitro fertilization or a history of miscarriages.
How is a subchorionic bleed treated?
Your practitioner will likely ask you to avoid strenuous activity, exercise, and sex. If your hematoma is large and there's significant bleeding, you may be advised to restrict your activity further.