Citation, DOI & article data
Subchorionic hemorrhage occurs when there is perigestational hemorrhage and blood collects between the uterine wall and the chorionic membrane in pregnancy. It is a frequent cause of first and second trimester bleeding.
It typically occurs within the first 20 weeks of gestation. When seen in the first 10-14 days of gestation, they are also termed implantational bleeds.
- crescentic collection with elevation of the chorionic membrane
- depending on the time elapsed since bleeding, the collection will have variable echotexture
- acute: hyperechoic and may be difficult to differentiate from the adjacent chorion
- subacute-chronic: decreasing echogenicity with time
- in almost all cases there is an extension of the hematoma towards the margin of the placenta 3
In early pregnancy, a subchorionic hemorrhage is considered small if it is <20% of the size of the sac, medium-sized if it is 20-50% 9, and large if it is >50-66% of the size of the gestational sac 5.
Large hematomas by size (>30-50%) and volume (>50 mL) worsen the patient's prognosis 9.
Treatment and prognosis
Fetal outcome is dependent on the size of the hematoma, maternal age, and gestational age 2. In most cases, the hematoma gradually decreases in size on follow-up and can resolve over 1-2 weeks 9. A subchorionic hemorrhage places the gestation at increased risk of:
If the collection extends up to the internal os and/or there is dilatation of the internal cervical os, this is an indication of extremely poor prognosis, almost always leads to impending miscarriage.
General imaging differential considerations include:
- 1. Bennett GL, Bromley B, Lieberman E et-al. Subchorionic hemorrhage in first-trimester pregnancies: prediction of pregnancy outcome with sonography. Radiology. 1996;200 (3): 803-6. Radiology (abstract) - Pubmed citation
- 2. Trop I, Levine D. Hemorrhage during pregnancy: sonography and MR imaging. AJR Am J Roentgenol. 2001;176 (3): 607-15. AJR Am J Roentgenol (full text) - Pubmed citation
- 3. Abu-yousef MM, Bleicher JJ, Williamson RA et-al. Subchorionic hemorrhage: sonographic diagnosis and clinical significance. AJR Am J Roentgenol. 1987;149 (4): 737-40. AJR Am J Roentgenol (abstract) - Pubmed citation
- 4. Norman SM, Odibo AO, Macones GA et-al. Ultrasound-detected subchorionic hemorrhage and the obstetric implications. Obstet Gynecol. 2010;116 (2 Pt 1): 311-5. doi:10.1097/AOG.0b013e3181e90170 - Pubmed citation
- 5. Nagy S, Bush M, Stone J et-al. Clinical significance of subchorionic and retroplacental hematomas detected in the first trimester of pregnancy. Obstet Gynecol. 2003;102 (1): 94-100. - Pubmed citation
- 6. Ball RH, Ade CM, Schoenborn JA et-al. The clinical significance of ultransonographically detected subchorionic hemorrhages. Am. J. Obstet. Gynecol. 1996;174 (3): 996-1002. Am. J. Obstet. Gynecol. (link) - Pubmed citation
- 7. Pearlstone M, Baxi L. Subchorionic hematoma: a review. Obstet Gynecol Surv. 1993;48 (2): 65-8. - Pubmed citation
- 8. Sauerbrei EE, Pham DH. Placental abruption and subchorionic hemorrhage in the first half of pregnancy: US appearance and clinical outcome. Radiology. 1986;160 (1): 109-12. Radiology (abstract) - Pubmed citation
- 9. Juliana Leite, Pamela Ross, A. Cristina Rossi, Philippe Jeanty. Prognosis of Very Large First‐Trimester Hematomas. (2006) Journal of Ultrasound in Medicine. 25 (11): 1441. doi:10.7863/jum.2006.25.11.1441 - Pubmed
- 10. Howard T. Heller, Elizabeth A. Asch, Sara M. Durfee, Robin P. Goldenson, Hope E. Peters, Elizabeth S. Ginsburg, Peter M. Doubilet, Carol B. Benson. Subchorionic Hematoma: Correlation of Grading Techniques With First‐Trimester Pregnancy Outcome. (2018) Journal of Ultrasound in Medicine. 37 (7): 1725. doi:10.1002/jum.14524