Extravasated Pudendal Artery Pseudoaneurysm Presenting as a Large Vaginal Hematoma Following Uncomplicated Delivery
Authors: DeVillers Megan , Arnold Thomas , Lutz Dennis 
Published: July 2024

Body of Abstract: (1) To report a case of an extravasated pudendal pseudoaneurysm presenting as vaginal hematoma following an uncomplicated delivery. (2) To discuss alternatives of management of vulvar hematomas.

Introduction: Postpartum hemorrhage is a leading cause of maternal mortality and can infrequently (1/300-1/1500 deliveries) be caused by vulvar hematomas. Vulvar hematomas are typically small and resolve with conservative treatment. Rarely, they can develop rapidly, posing a significant risk to the patient. Risks for vulvar hematomas include a prolonged second stage of labor, multiple gestation, operative vaginal delivery, episiotomy, and vaginal laceration. Extravasation from a pseudoaneurysm in the pelvic arteries is a rare cause of vulvar hematomas (< 5% of cases) with >75% involving the uterine artery. Pseudoaneurysms typically result from damage to vasculature during a traumatic delivery. Spread into the retroperitoneal space can lead to shock and eventual demise if improperly managed. This case illustrates the exceptionally rare occurrence of a pudendal artery pseudoaneurysm with rapidly expanding potentially catastrophic hematoma formation.

Case Summary: Presented is a 21-year-old G2P1011 patient at 39w5d with a large vaginal hematoma diagnosed shortly following spontaneous vaginal delivery. The case initially presented to the hospital one hour after spontaneous rupture of membranes with an unremarkable pregnancy. Normal labor ensued and stage II of labor lasted one hour with an uncomplicated nonoperative vaginal delivery.

Postpartum a significant increase in fundal height was noted. Cytotec was given and bladder catheterization removed 800 ml urine. Abdominal pain increased. Vital signs were normal. Exam revealed a large posterior vaginal wall swelling extending upward, but without active bleeding. A computerized tomography (CT) scan of the abdomen/pelvis revealed a 9.7 X 10.5 X 13.2 cm pelvic hematoma arising from the posterior vaginal wall with extension cephalad into the perirectal space and right adnexa. Evidence of active bleeding and bilateral hydronephrosis were reported. Hemoglobin was 10.1, down from admission 12.5. Symptoms included worsening abdominal pain and dizziness. Based on the active bleeding noted on CT scan and the progressive symptoms, the patient was transferred to a tertiary care center.

Upon tertiary center admission the patient was tachycardic and hypotensive (P 153 and BP 101/61). Hemoglobin was 9.3. Physical exam was unchanged. Interventional radiology recommended and patient underwent embolization of bilateral uterine arteries for treatment of a diagnosed pseudoaneurysm with extravasation of the right pudendal artery.

Postpartum day 1, mild right lower quadrant pain was felt to be consistent with the embolization. Hemoglobin decreased to 6.5, and the patient received one unit of packed red blood cells (PRBCs). Clinically, ambulation was tolerated, but tachycardia and hypotension remained and there was decreased swelling. Hemoglobin remained low at 6.8, and another unit of PRBCs was given. Hospital course thereafter was uneventful and discharge was on day 3.

Discussion: This case describes a vaginal hematoma and pudendal artery pseudoaneurysm as a very rare but potentially life-threatening postpartum hemorrhage following vaginal delivery. Association with an uncomplicated pregnancy and delivery, involvement of the pudendal artery with an expanding large hematoma dissecting the retroperitoneal space creating a hemodynamically unstable situation are only rarely seen concurrently.

Hematoma treatment starts conservatively, utilizing ice, rest, and pain control if patient is hemodynamically stable and the hematoma is small. When large, rapidly expanding, or the patient is hemodynamically unstable, surgical intervention or artery embolization should be considered when imaging identifies the source of bleeding. Imaging may include ultrasound, CT, CT angiography, and magnetic resonance imaging as options for localization of hematoma. No superior mode of evaluation is identified.

Pseudoaneurysms following delivery have most commonly been described in the uterine arteries with only a handful of case reports documenting other sources including the obturator, labial, vaginal, and internal pudendal arteries. Our case demonstrates that extravasated pelvic artery pseudoaneurysms can present in benign appearing nonoperative deliveries and should be considered in the differential diagnosis as a source of post-partum hemorrhage. Recently, pseudo-aneurysms have more commonly been treated with IR artery embolization as it is a less invasive and better tolerated procedure by patients. Tsumagari et al suggested an algorithm proposing vulvovaginal hematomas should be observed versus surgically evacuated, whereas upper vaginal hematomas should undergo CT angiography for assessment for selective arterial embolization.

Conclusion: Pseudoaneurysms of the pudendal artery with hematoma formation occurring in an uncomplicated delivery are an extremely rare cause of potentially life-threatening hemorrhage as reported in only a handful of cases. Because of their potential for catastrophic sequelae, they should be considered in the differential diagnosis of expanding upper vaginal hematomas. This case depicts the importance and success of rapid identification and embolization of pudendal artery pseudoaneurysm to prevent mortality.