From the Guidelines
Small subchorionic hemorrhage is a relatively common finding in early pregnancy and is not necessarily abnormal, with studies suggesting that it can occur in up to 27% of pregnancies with first-trimester bleeding 1. When evaluating vaginal bleeding in the first trimester, ultrasound is the primary imaging modality, and it can usually differentiate between a normal intrauterine pregnancy with or without a subchorionic hematoma, nonviable intrauterine pregnancy, gestational trophoblastic disease, and ectopic pregnancy 1. Some key points to consider include:
- The risk of miscarriage associated with first-trimester bleeding is approximately 12% 1
- Ultrasound findings, correlated with serum human chorionic gonadotropin (hCG) levels and clinical presentation, can usually differentiate causes of first-trimester bleeding 1
- Small subchorionic hemorrhages, in particular, are often monitored rather than treated, with follow-up ultrasounds to track whether the hemorrhage is resolving 1 It is essential to guard against injury to normal pregnancies by avoiding overinterpretation of a single ultrasound and misunderstanding the usefulness of the discriminatory level or serial values of hCG 1. In the context of real-life clinical medicine, a small subchorionic hemorrhage in early pregnancy is generally not a cause for immediate concern, and management typically involves monitoring and follow-up ultrasounds rather than specific treatment.
From the Research
Subchorionic Hemorrhage in Early Pregnancy
- Subchorionic hemorrhage (SCH) is a condition where blood accumulates between the chorion and decidua basalis due to their separation, and it is common in patients with threatened abortion in early pregnancy 2.
- SCH can be detected by ultrasound and mainly manifests as a hypoechoic or anechoic crescent-shaped fluid dark area on ultrasound images 2.
- The occurrence of SCH may be related to several factors, such as abnormal coagulation function, autoimmune factors of pregnant women, assisted reproduction, drug use during pregnancy, and reproductive tract infection, although its exact etiology remains unclear 2.
Clinical Significance of Subchorionic Hemorrhage
- Subchorionic hemorrhage is a frequent cause of first and second-trimester bleeding and has a grave prognosis, with an unfavorable outcome in 71% of cases 3.
- The outcome of pregnancies with SCH correlates well with the relative and absolute size of the hematoma, severity of vaginal bleeding, change in hematoma size on follow-up examination, and presence of pain 3.
- The size of the hematoma estimated as a fraction of gestational sac size significantly correlates with first-trimester pregnancy loss 4.
Pregnancy Outcomes with Subchorionic Hemorrhage
- Subchorionic hematomas in early pregnancy are associated with an increased risk of spontaneous abortion, with a higher rate of pregnancy failure when diagnosed at or before 7 weeks 4, 5.
- The presence of a hematoma does not affect the frequency of preterm delivery, but it is associated with an increased risk of placental abruption and preterm delivery 6.
- The critical factor in determining pregnancy outcome is the site of the hematoma, not its volume, with hematomas in the corpus or fundus of the uterus being more likely to result in abortion 5.