Ultrasound Case of the Month: Delayed Postpartum Hemorrhage
/Case:
A middle aged female patient presented to the emergency department with vaginal bleeding and severe uterine pain. She underwent cesarean section five days prior and her bleeding had ceased, but it returned again on the day of presentation. She had no known bleeding disorder or other medical history. She was hypotensive to 80/40, tachycardic, and appeared diaphoretic and ill. Vaginal exam showed brisk vaginal bleeding. Two large-bore IVs were placed and massive transfusion was started. A bedside uterine ultrasound was performed that demonstrated heterogenous intrauterine contents concerning for a clot and the obstetrics team was consulted.
Transabdominal view of uterus in transverse orientation
Transabdominal view of uterus in longitudinal plane
Secondary postpartum hemorrhage is defined as hemodynamically significant blood loss (typically >500 mL) greater than 24 hours, but less than 12 weeks after delivery.[1] Delayed hemorrhage occurs in 2% of vaginal deliveries and C-sections, and the most common causes include: retained products of conception (RPOC), subinvolution of the placental bed, infection, and inherited coagulopathy.[2,3] RPOC are more common in vaginal delivery, whereas endometritis is more common in cesarean section. Presentation typically includes bleeding with signs of hypovolemia as well as pelvic pain, fever, and uterine tenderness. Initial workup should include CBC, coagulation studies, type and screen. hCG testing assists with diagnosis of choriocarcinoma, RPOC, and new pregnancy.[4] Ultrasound with color doppler is the imaging modality of choice, but CT and MRI can be useful in specific cases.[5]
Ultrasound Evaluation:
Emergency physician performed ultrasound has been used to diagnose RPOC as the cause of secondary postpartum hemorrhage and to differentiate from alternative diagnosis, such as arteriovenous malformation (AVM).[6,7] Evaluation can begin with transabdominal views with general evaluation for intraperitoneal free fluid suggestive of alternative diagnoses such as internal hemorrhage or uterine rupture. Transvaginal ultrasound is preferred for definitive diagnosis as it allows better image resolution and evaluation of vascularity. Evaluation for RPOC is the primary focus of imaging as endometritis is often amenable to conservative treatment with antibiotics, whereas RPOC often necessitates procedural evacuation. Presence of an intrauterine mass or endometrial stripe thickness greater than 10 mm is suggestive of RPOC, but similarity in appearance with physiologically normal blood clots or complex fluid can lead to a high false positive rate of 30-40%.[8,9] Presence of an endometrial mass is more indicative of RPOC with 79% sensitivity and 89% specificity.[8] Color doppler is useful in diagnosing RPOC with about 80% of cases having vascularity, though avascular RPOC can be seen.[10] Presence of vascularity should not occur in endometritis.
Arteriovenous Malformation:
Uterine arteriovenous malformations are the result of direct connection between the uterine artery and myometrial venous plexus.[11] AVMs can occur after instrumentation of the uterus, such as in a cesarean section, and are rare in comparison to RPOC. Differentiation of these entities is important as typical treatment of RPOC with dilation and curettage (D&C) can cause life threatening hemorrhage, and treatment typically involves hysterectomy or embolization of the uterine artery. AVM can be differentiated from RPOC by isolation of the vascularity to the myometrium, as compared to vascularity that extends into the endometrial space in RPOC.[12] On ultrasound, AVMs will typically appear as tubular, hypoechogenic structures in the myometrium with bidirectional flow on color doppler.[11] If there is concern for AVM, CT angiography can be helpful to further evaluate for vascular malformations.[13]
Subinvolution of Placental Bed:
Subinvolution of the placental bed is failure of involution of the remodeled uteroplacental vasculature after delivery. It can only be formally diagnosed by histopathology. Ultrasound will show presence of widely patent uteroplacental vasculature at the previously documented placental implantation site without evidence of retained products of conception.[14,15]
Endometritis:
Ultrasound appearance of endometritis can be similar to normal postpartum appearance as well as RPOCs. Thickening of the endometrium with fluid or echogenic debris may be present, but the endometrium can also appear normal. Presence of ring down artifact, suggestive of gas in the endometrial cavity is suggestive of endometritis, but air can be seen for up to three weeks in the normal postpartum period. Differentiation of endometritis relies on the presence of clinical signs of infection and physical exam findings such as fever and cervical discharge.[16,17]
Case Resolution:
Further ultrasound images were obtained, and based on the echogenicity of the uterine contents in the absence of evidence of endometritis, there was a high suspicion for retained products of conception. She was emergently taken to the operating room for hysteroscopy and D&C that showed enlarged uterus with approximately two liters of intrauterine blood and clot that was evacuated. Fundal massage, oxytocin, methylergonovine, and tranexamic acid were administered and bleeding ceased. Repeat ultrasound demonstrated a thin endometrial stripe. She had an uneventful postoperative course and was discharged two days later.
Take Home Points:
Ultrasound should be the initial imaging modality for evaluation of secondary postpartum hemorrhage.
Endometrial stripe thickness > 10 mm and intrauterine heterogeneous echogenic mass are suggestive of retained products of conception.
Vascularity extending into the myometrium is suggestive of AVM.
Endometritis can mimic RPOC and physical exam and clinical signs should be used to differentiate these entities.
While ultrasound remains the initial study of choice, diagnosis of retained products of conception should involve consultation with obstetric colleagues. In the ER, primary objectives include ruling out new pregnancy, evaluation for free fluid, consideration of alternative diagnoses and expert consultation.
AUTHORED BY Logan Walsh, MD
Dr. Walsh (@loganwalsh) is a PGY-4 and Chief Resident in Emergency Medicine at the University of Cincinnati
Peer review by Jessica Baez, MD and Lori Stolz, MD RDMS
Dr. Baez (@blonde_doctr) is an Assistant Professor of Emergency Medicine at the University of Cincinnati and Assistant Residency Director.
Dr. Stolz (@sonostolz) is an Associate Professor of Emergency Medicine at the University of Cincinnati and Director of the Ultrasound Fellowship.
editing and layout by ARTHUR broadstock, md
Dr. Broadstock (@BroadstockMD) is a PGY-3 in Emergency Medicine at the University of Cincinnati and Resident Editor of Ultrasound of the Month.
References:
1. Committee on Practice Bulletins-Obstetrics. Practice Bulletin No. 183: Postpartum Hemorrhage. Obstet Gynecol. 2017;130(4):e168-e186. doi:10.1097/AOG.0000000000002351
2. Alexander J, Thomas P, Sanghera J. Treatments for secondary postpartum haemorrhage. Cochrane Database Syst Rev. 2002;(1):CD002867. doi:10.1002/14651858.CD002867
3. Dossou M, Debost-Legrand A, Déchelotte P, Lémery D, Vendittelli F. Severe secondary postpartum hemorrhage: a historical cohort. Birth. 2015;42(2):149-155. doi:10.1111/birt.12164
4. Belfort MA. Secondary (late) postpartum hemorrhage. In: Simpson LL, Barss VA, eds. UpToDate. UpToDate; 2020. https://www.uptodate.com/contents/secondary-late-postpartum-hemorrhage?search=retained%20products%20of%20conception&source=search_result&selectedTitle=2~34&usage_type=default&display_rank=2
5. Iraha Y, Okada M, Toguchi M, et al. Multimodality imaging in secondary postpartum or postabortion hemorrhage: retained products of conception and related conditions. Jpn J Radiol. 2018;36(1):12-22. doi:10.1007/s11604-017-0687-y
6. Adkins K, Minardi J, Setzer E, Williams D. Retained Products of Conception: An Atypical Presentation Diagnosed Immediately with Bedside Emergency Ultrasound. Case Rep Emerg Med. 2016;2016:9124967. doi:10.1155/2016/9124967
7. Scribner D, Fraser R. Diagnosis of Acquired Uterine Arteriovenous Malformation by Doppler Ultrasound. J Emerg Med. 2016;51(2):168-171. doi:10.1016/j.jemermed.2016.04.028
8. Durfee SM, Frates MC, Luong A, Benson CB. The sonographic and color Doppler features of retained products of conception. J Ultrasound Med. 2005;24(9):1181-1186; quiz 1188-1189. doi:10.7863/jum.2005.24.9.1181
9. Shen O, Rabinowitz R, Eisenberg VH, Samueloff A. Transabdominal sonography before uterine exploration as a predictor of retained placental fragments. J Ultrasound Med. 2003;22(6):561-564. doi:10.7863/jum.2003.22.6.561
10. Kamaya A, Petrovitch I, Chen B, Frederick CE, Jeffrey RB. Retained products of conception: spectrum of color Doppler findings. J Ultrasound Med. 2009;28(8):1031-1041. doi:10.7863/jum.2009.28.8.1031
11. Yoon DJ, Jones M, Taani JA, Buhimschi C, Dowell JD. A Systematic Review of Acquired Uterine Arteriovenous Malformations: Pathophysiology, Diagnosis, and Transcatheter Treatment. AJP Rep. 2016;6(1):e6-e14. doi:10.1055/s-0035-1563721
12. Timmerman D, Wauters J, Van Calenbergh S, et al. Color Doppler imaging is a valuable tool for the diagnosis and management of uterine vascular malformations. Ultrasound Obstet Gynecol. 2003;21(6):570-577. doi:10.1002/uog.159
13. Ghai S, Rajan DK, Asch MR, Muradali D, Simons ME, TerBrugge KG. Efficacy of embolization in traumatic uterine vascular malformations. J Vasc Interv Radiol. 2003;14(11):1401-1408. doi:10.1097/01.rvi.0000096761.74047.7d
14. Petrovitch I, Beatty M, Jeffrey RB, Heerema-McKenney A. Subinvolution of the placental site. J Ultrasound Med. 2009;28(8):1115-1119. doi:10.7863/jum.2009.28.8.1115
15. Triantafyllidou O, Kastora S, Messini I, Kalampokis D. Subinvolution of the placental site as the cause of hysterectomy in young woman. BMJ Case Rep. 2021;14(2). doi:10.1136/bcr-2020-238945
16. Mulic-Lutvica A, Axelsson O. Postpartum ultrasound in women with postpartum endometritis, after cesarean section and after manual evacuation of the placenta. Acta Obstet Gynecol Scand. 2007;86(2):210-217. doi:10.1080/00016340601124086
17. Cicchiello LA, Hamper UM, Scoutt LM. Ultrasound evaluation of gynecologic causes of pelvic pain. Obstet Gynecol Clin North Am. 2011;38(1):85-114, viii. doi:10.1016/j.ogc.2011.02.005
