Subchorionic hemorrhage (SCH) — also called subchorionic hematoma — is one of the most common findings on first-trimester ultrasounds in women with bleeding. It occurs when blood pools between the chorionic membrane and the uterine wall.
What Is a Subchorionic Hemorrhage?
When the fertilised egg implants in the uterine wall, small blood vessels can tear slightly, creating a pocket of blood. This blood pool (hematoma) sits between the gestational sac and the uterine lining. Most are small and self-resolve without treatment.
Symptoms
| Symptom | Notes |
|---|---|
| Light vaginal bleeding (red or brown) | Most common presentation |
| Cramping | May accompany bleeding |
| No symptoms | Many SCH are found incidentally on routine scan |
| Heavy bright red bleeding | Warrants urgent medical review |
How It Is Diagnosed
SCH is diagnosed on ultrasound — either transvaginal (most sensitive for small hematomas) or transabdominal. The sonographer measures the size of the hematoma relative to the gestational sac. Small hematomas (less than 20% of gestational sac size) have a very good prognosis.
Management
There is no treatment proven to resolve SCH faster. Management is watchful waiting:
- Pelvic rest (avoiding penetrative sex and vigorous exercise) until resolved
- Progesterone supplements are sometimes prescribed — evidence is mixed
- Repeat ultrasound at 1–2 weeks to check if hematoma is resolving
- Monitoring for signs of placental abruption in larger hematomas
What the Research Shows
Most small SCH resolve completely by the second trimester without affecting the pregnancy. Large hematomas (especially those larger than the gestational sac) carry a higher risk of miscarriage and preterm birth. Location also matters — retroplacental (behind the placenta) hematomas have worse outcomes than marginal ones.
Important
Any vaginal bleeding in pregnancy deserves medical assessment, especially in the first trimester. Don't assume it's 'just implantation bleeding' without investigation.