Learning objectives
(1) To review the relationship between subchorionic haematomas and adverse pregnancy outcomes
(2) To provide guidance on assessing subchorionic haematomas and how its characteristics may predict adverse outcomes
Background
Subchorionic haematoma (SCH) is a common finding on first trimester ultrasounds, with a varying incidence of 4-22% [1]. The majority of SCHs are benign and affected pregnancies often will proceed to deliver a healthy, term baby. However, the diagnosis of SCHs can cause significant anxiety among expectant parents and confusion for clinicians.
Several studies have produced conflicting evidence where SCH has been shown to be associated with higher rates of adverse pregnancy outcomes, including miscarriages, fetal growth restriction, placental abruption, pre-eclampsia and preterm birth [2]....
Imaging findings OR Procedure details
Case Report: A 40-year-old woman, G1P0, presented at 13 weeks gestation to emergency department with heavy, painless vaginal bleeding. Prior to this presentation, she has had an uneventful first trimester with a normal dating scan and low risk aneuploidy screening.
A pelvic ultrasound was arranged by emergency which demonstrated a live intrauterine pregnancy and a large subchorionic haematoma overlying the internal os (see Figure 1). She was admitted overnight for observations and discharged the next day.
[Fig 1]
She presented two weeks later, at 15...
Conclusion
The association between subchorionic haematomas and adverse pregnancy outcomes is not concrete, in particularly when they are relatively small. Studies suggested that the earlier (gestation) the diagnosis of SCH and the larger the estimated haematoma size as a fraction of gestational sac size, the higher likelihood of adverse outcomes. Although no guidelines exist to guide radiologists, it would be appropriate to report cautiously when faced with a large haematoma on the first trimester ultrasound.
References
Mazzariol, FS, Roberts, J, Oh, SK, Ricci, Z, Koenigsberg, M & Stein, MW. Pearls and pitfalls in first-trimester obstetric sonography. Clinical Imaging. 2015; Volume 39: p176-185.
Günay T & Yardımcı OD. How does subchorionic hematoma in the first trimester affect pregnancy outcomes? Archives of Medical Science [serial on the Internet] 2019 [cited 2022 Mar 20]; 18(3) [8 pages]. Available from: https://www.archivesofmedicalscience.com/How-does-subchorionic-hematoma-in-the-first-trimester-affect-pregnancy-outcomes-,113645,0,2.html
Tuuli, MG, Norman, SM, Odibo, AO, Macones, GA & Cahill, AG. Perinatal outcomes in women with subchorionic hematoma: a systematic review and meta-analysis. Obstetrics...