Subchorionic Hematoma Size and Adverse Pregnancy Outcomes: A Systematic Review of Evidence from 2022 to 2025

Abstract

Background: SCH represents one of the most common sonographic discoveries during early gestation, yet the predictive significance of hematoma dimensions in forecasting unfavorable pregnancy outcomes remains inadequately established. This comprehensive review aimed to establish the correlation between SCH dimensions and adverse gestational outcomes, including pregnancy loss, premature delivery, and FGR.

Methods: This comprehensive review was conducted following PRISMA 2020 standards. A thorough literature search across PubMed, Scopus, Web of Science, Google scholar, and Cochrane library was performed to identify relevant studies on this subject matter from January 2022 through May 2025. Eligible investigations included original observational research and systematic reviews that documented SCH dimensions and at least one unfavorable pregnancy outcome. Study assessment was performed using the NOS. Due to variations in SCH size definitions and outcome reporting, a descriptive synthesis was performed.

Results: 14 articles were incorporated, including over 5,000 natural conception and assisted reproductive technology (ART) pregnant women. There was a consistent dose -response graph between the increasing SCH size and adverse event. FGR was independently related to large SCH with adjusted odds ratios between 5.31 and 10.21 in cohort studies (largest cohort studies). A steady SCH-to-gestational-sac ratio of at least 25% was considered a good cutoff point of quantitative value used in predicting preterm birth. Across various studies, there was high risk of miscarriage especially when SCH was found prior to the 7 week mark of gestation. Importantly, however, the pooled evidence were not able to demonstrate statistically significant association between SCH presence alone and preterm delivery; stratification based on a size was very crucial to the detection of a high-risk case. The results of ART populations were not consistent with some studies eventually proving that there is a higher risk of miscarriage and others showing no show of significant results.

Conclusion: The size of SCH is a better prognostic variable, as opposed to the presence, to adverse pregnancy outcomes. To have meaningful risk stratification, standardized measurement protocols, in particular the gestational-sac-ratio method, should be used in the first-trimester ultrasonographic reporting. Further multicentre research is required that can substantiate these results and come up with evidence-based clinical principles.