What is the significance of a growing subchorionic hemorrhage (SCH), increasing from 9 x 7 x 6 mm to 30 x 27 x 13 mm, between approximately 9 and 12 weeks gestation?

From the Guidelines

A subchorionic hemorrhage that has increased in size from 9 x 7 x 6 mm at nine weeks to 30 x 27 x 13 mm at 12 weeks gestation is a significant concern and warrants close medical attention. This growth suggests active bleeding between the uterine wall and the gestational sac, which may be associated with an increased risk of pregnancy complications such as miscarriage or preterm labor 1. The size of the hemorrhage places it in a moderate risk category, with approximately 10-20% risk of pregnancy complications.

Key Considerations

• The primary imaging modality for evaluating first-trimester vaginal bleeding is ultrasound, which can usually differentiate causes of bleeding, including normal intrauterine pregnancy with or without a subchorionic hematoma, nonviable intrauterine pregnancy, gestational trophoblastic disease, and ectopic pregnancy 1.
• Close monitoring with follow-up ultrasounds every 1-2 weeks is recommended to track the hemorrhage size and assess fetal development.
• Pelvic rest, avoiding sexual intercourse and strenuous activity, is advisable until the hemorrhage resolves.
• Most subchorionic hemorrhages resolve spontaneously by 20 weeks gestation, but larger ones like this may take longer to reabsorb.

Management and Prognosis

• The bleeding occurs when maternal blood collects between the chorion (outer fetal membrane) and the uterine wall, potentially from imperfect implantation or placental margin development.
• Any active vaginal bleeding should prompt immediate medical evaluation.
• While no specific medication is typically prescribed for subchorionic hemorrhage, close monitoring and pelvic rest are essential to minimize the risk of pregnancy complications.
• The patient should be aware of the potential risks and complications associated with a subchorionic hemorrhage of this size and be closely monitored throughout the pregnancy.

From the Research

Significance of Subchorionic Haemorrhage

The significance of a subchorionic haemorrhage that is 30 x 27 x 13 mm at 12 weeks gestation, previously 9 x 7 x 6 mm at about nine weeks gestation, can be understood by considering the following points:

• The size of the haemorrhage has increased significantly over a period of three weeks, which may indicate a higher risk of pregnancy-related complications 2.
• Studies have shown that subchorionic haemorrhage is associated with adverse pregnancy outcomes such as miscarriage, preterm birth, preeclampsia, and fetal growth restriction, although the exact etiology remains unclear 3, 4, 5.
• The location and size of the haemorrhage, as well as the presence of vaginal bleeding, are important factors in determining the prognosis of the pregnancy 4, 5.
• A study found that women with ultrasound-detected subchorionic hemorrhage before 22 weeks of gestation are at increased risk of placental abruption and preterm delivery, but not at increased risk of other adverse pregnancy outcomes 5.
• Another study established criteria for defining "large" subchorionic hematoma and found that large SCHs may indicate a high risk of pregnancy-related complications, particularly preterm delivery 2.

Key Factors to Consider

Some key factors to consider in this case are:

• The size of the haemorrhage: The haemorrhage has increased in size from 9 x 7 x 6 mm to 30 x 27 x 13 mm over a period of three weeks.
• The gestational age: The haemorrhage is present at 12 weeks gestation, which is a critical period for fetal development.
• The presence of vaginal bleeding: The study does not mention the presence of vaginal bleeding, which is an important factor in determining the prognosis of the pregnancy.
• The location of the haemorrhage: The study does not provide information on the location of the haemorrhage, which can affect the prognosis of the pregnancy.

Association with Pregnancy Outcomes

The association between subchorionic haemorrhage and pregnancy outcomes is complex and not fully understood. However, studies have shown that:

• Subchorionic haemorrhage is associated with an increased risk of placental abruption and preterm delivery 5.
• Large subchorionic haemorrhage may indicate a high risk of pregnancy-related complications, particularly preterm delivery 2.
• The presence of subchorionic fluid and subchorionic bleeding is common in early pregnancy and is not associated with embryonic death unless accompanied by clinical bleeding 6.