What is the management of subchorionic hemorrhage in obstetrics (OBs)?

Management of Subchorionic Hemorrhage in Obstetrics

For subchorionic hemorrhage (SCH) detected on ultrasound, management centers on serial ultrasound monitoring, activity modification with consideration of bed rest, and surveillance for adverse outcomes including placental abruption and preterm delivery, with specific attention to anticoagulation status and hematoma characteristics.

Initial Assessment and Diagnosis

• Transvaginal ultrasound is the primary imaging modality for diagnosing SCH, which occurs in 7-27% of pregnancies 1
• Document the location of the hematoma relative to the placenta, size (both absolute and relative to gestational sac), and presence of fetal cardiac activity 1
• Obtain quantitative beta-hCG level, complete blood count, and blood type/screen if not already on file 1
• Administer anti-D immunoglobulin (50 μg) to Rh-negative patients with vaginal bleeding to prevent alloimmunization 1
• Avoid pulsed Doppler ultrasound in the first trimester due to potential bioeffects on the developing embryo; instead use M-mode ultrasound or video clips to document cardiac activity 1

Risk Stratification

The prognosis correlates with specific ultrasound and clinical findings:

• Hematoma size (both relative and absolute) is the strongest predictor of adverse outcomes, with larger hematomas associated with worse prognosis 2
• Presence of fetal cardiac activity indicates better prognosis 1
• Severity of vaginal bleeding and presence of pain correlate with unfavorable outcomes 2
• Retroplacental hematomas have significantly higher miscarriage rates compared to subchorionic hematomas 3
• All hematomas extend to the placental margin 2

Management by Trimester

First Trimester Management

• Recommend bed rest at home for the duration of vaginal bleeding, as this approach is associated with fewer spontaneous abortions (9.9% vs 23.3%) and higher term pregnancy rates (89% vs 70%) compared to usual activity 4
• Perform serial ultrasound examinations at 7-day intervals until bleeding ceases, the hematoma disappears, or pregnancy outcome is determined 5, 4
• Most subchorionic hematomas will disappear by the end of the second trimester, though 2% of retroplacental hematomas may persist 3

Second and Third Trimester Management

• SCH in later pregnancy requires more intensive monitoring due to associations with significant maternal and fetal morbidity 6
• Perform serial growth ultrasounds and umbilical artery Doppler studies for second and third trimester SCH 5, 6
• Monitor for signs of hemodynamic instability in large SCH requiring hospitalization 5
• Consider blood transfusion if significant blood loss occurs 5, 6

Special Considerations for Anticoagulated Patients

• Women on direct oral anticoagulants (DOACs) should be switched immediately to low molecular weight heparin if pregnancy is discovered 5
• For women on anticoagulants who develop SCH, discontinue DOACs and switch to LMWH with early obstetric review and fetal monitoring 5
• The only known risk factors for SCH are maternal factor deficiency and anticoagulation therapy 6

Surveillance for Adverse Outcomes

Women with SCH are at increased risk for multiple complications:

• Placental abruption risk increases 2.6-fold (adjusted OR 2.6,95% CI 1.8-3.7) 7
• Preterm delivery risk increases 1.3-fold (adjusted OR 1.3,95% CI 1.1-1.5), with 15.5% delivering preterm compared to 10.5% without SCH 7
• Additional risks include preterm prelabor rupture of membranes, intrauterine growth restriction, fetal demise, and neonatal pulmonary morbidity 6, 3
• Cesarean section rates are higher (60% vs lower rates in controls) 3
• Neonatal outcomes are worse, including lower birth weight, lower Apgar scores, and increased NICU admissions 3

Common Pitfalls

• Do not confuse early first trimester SCH with normal decidual bleeding 1
• Distinguish SCH from subamniotic hematomas and placental abruption, which have different management implications 1
• Pay meticulous attention to placental margins during ultrasound examination, as all hematomas extend to the placental margin 2
• Second and third trimester SCH can be more difficult to diagnose and requires heightened clinical suspicion 1