Uneventful vaginal delivery after spontaneous resolution of uterine artery pseudoaneurysm

Abstract

Uneventful vaginal delivery after spontaneous resolution of uterine artery pseudoaneurysmSir, A recent article in AOGS focused on primary postpartum hemorrhage (<24 h postpartum), showing increase in its incidence in the Netherlands (1); however, secondary postpartum hemorrhage (>24 h postpartum) was not mentioned. We recently demonstrated that uterine artery pseudoaneurysm (UAP), a causal disorder of secondary postpartum hemorrhage, can occur more frequently (3-6/1000 deliveries) than previously expected (2). Hence, obstetricians may encounter this disorder more frequently.Delivery-associated or abortion-associated UAP may cause massive hemorrhage, requiring transarterial embolization (TAE) (2), but some UAPs resolve spontaneously (3). To our knowledge, the pregnancy course subsequent to UAP resolution has not been reported.Uneventful evacuation was performed for a missed abortion at the 8th week in a primiparous woman. Although she was asymptomatic, vaginal gray-scale ultrasound (performed routinely 1 week postabortion) revealed an intrauterine hypoechoic mass with swirling blood flow on color Doppler (Figure 1), suggestive of UAP (2-4). Considering the patient's wishes, we followed her as an outpatient. At 10 weeks post-abortion, she had moderate vaginal bleeding: enhanced computed tomography revealed an intrauterine mass with relatively weak but evident enhancement (inset of Figure 1). The bleeding spontaneously resolved. We weighed the balance between performing TAE for a patient with no current bleeding and the possibility of future rupture of UAP and agreed to closely monitor her without TAE. She had no further bleeding. Gray-scale ultrasound and color Doppler revealed a gradual decrease in the size of the intrauterine hypoechoic mass and the flow, which completely disappeared 11 weeks after abortion.One year later, she became pregnant and gave birth vaginally to a term infant (3148 g, Apgar score 8/9 at 1/5 min), with a total bleeding of 225 mL. Her postpartum course was uneventful. Ultrasound check-ups performed repeatedly until 4 weeks postpartum revealed no evidence of UAP or intrauterine bleeding/hematoma indicative of vessel injury.We previously showed that some UAP can resolve spontaneously without TAE, suggesting that a conservative strategy can be employed in some women (3), but this was solely based on short-term observations. The UAP sac may have been thrombosed, leading to UAP disappearance (2,4). Although a thrombosed sac is invisible, it is expected to be present beneath the uterine lumen. The mechanism of UAP occurrence after nontraumatic vaginal delivery is unclear; however, the shear-force at the site during delivery may tear or injure the artery, causing UAP (5). Hence, we were concerned about "tear or rupture" of the thrombosed sac as the movement of the infant through the birth canal could stretch the site and injure the thrombosed sac, causing hemorrhage. However, this did not happen in this woman.With increasing awareness, less symptomatic UAPs are likely to be diagnosed, with more wo...