Postpartum hemorrhage (PPH) is a major challenge for obstetricians. Of all maternal mortalities, 11% is due to obstetric hemorrhage, which is still one of the most important causes of maternal mortality (
1). Excessive vaginal bleeding from 24h after delivery up to 6 weeks is defined as late postpartum hemorrhage.
There is no obvious definition for quantity of blood loss and this can vary from increased lochia to massive hemorrhage; the diagnosis is therefore subjective. The overall incidence of secondary postpartum hemorrhage is 0.47% - 1.44% (
There are different etiologies for secondary postpartum hemorrhages and management depends on the cause. In spite of the association with minor morbidities, there are still requirements of readmission to hospital, use of antibiotics, and surgical intervention. In rare cases, major hysterectomy, arterial ligation or radiological intervention is possible and despite the use of all available interventions, maternal death may still result from massive secondary postpartum hemorrhage (
1). All common causes of delayed PPH, with exclusion of endometritis and retained product of conception, were ruled out and bilateral uterine arteries were ligated. Hysterectomy was not an option for a young fertile woman.
Since pseudoaneurysm is not prevalent and in some cases small in size, the diagnosis is only possible if sufficient clinical suspicion exists. Good quality transvaginal ultrasonography with Doppler is usually the first key to determine the diagnosis, but angiography is the gold standard (
Abu Ghazza et al. reviewed 16 cases of PPH with pseudoaneurysm and showed that transvaginal sonography was successful in diagnosning 12 of these cases. A characteristic vascular appearance with a “to and from" sign can be seen in Doppler results of pseudoaneurysms that could differentiate it from other possible diagnoses such as fibroid, hematoma or an abscess (
3). 3.1. Vascular Surgery Recommendation
Uterine arteriovenous malformation leading to postpartum hemorrhage is rare and has an unknown definite incidence. AVM can be congenital but is commonly acquired when it is presented with secondary postpartum hemorrhage, because of the fact that sufficient time is necessary for a pseudoaneurysm to initiate (
4). The most common cause of PPH is endometritis or retained products of conception, which could be managed with antibiotics or through an evacuation.
AVMs are abnormal arteriovenous connections that can occur anywhere in the body. Abnormal development of primitive vessels that form connections between pelvic arteries and veins in the uterus can be a way in which they are produced.
They are characterized by several feeding and draining vessels with an interconnecting nidus with turbulent flow. AVMs are rare and are associated with PPH in less than 1% of cases.
Acquired vascular malformation results from iatrogenic or traumatic injury to the uterine artery vascular bed (
Abu-Ghazza also showed that out of 16 patients in his study, 10 underwent a cesarean section, 3 of them had a uterine evacuation, and another 3 had a normal vaginal delivery without any complications (
In terms of etiology, a cesarean section at advanced dilatation with uterine angle extension is the most common antecedent event, where direct trauma and suturing around the uterine artery bed cause abnormal vascular connections. Failure to completely suture causes the bleeding vessels at the apex angle to tear and leads to leakage into the surrounding tissues (
6). Recent curettage, particularly in situations in which it is difficult or the placental tissue is very adherent, may be also a direct cause of vascular trauma. When these abnormalities present after an uncomplicated vaginal delivery, it is proposed that the vascular bed of the myometrium is disrupted by the mechanism of delivery or, in fact, more likely that the malformation pre-existed and only presented after delivery ( 6). 3.2. Interventionist Aspect
Embolization of the pelvic vascular system is well established for PPH in general. It is also minimally invasive. If the site of hemorrhage is accurately identified, selective embolization can preserve the normal vascular supply of the uterus. Abu-Ghazza describes a high degree of success in managing vascular malformations with embolization (
3). Embolization success rates were reported as 85% - 95% ( 7, 8). As flow through the vessels returns over time, it preserves both the uterus and fertility ( 9).
Embolization is performed through percutaneous catheterization of the femoral artery. Typically, a temporary agent such as a gelatin sponge is used to decrease the perfusion pressure and to stop hemorrhage in PPH (
Proximal and non-selective embolization present a higher risk for the pelvic blood supply (
9). In our case, which was an emergency situation with unstable hemodynamic conditions and no suspicion of AVM, ligation of the bilateral internal iliac arteries was primarily performed. AVM with feeding from the femoral artery branch is very rare and has not previously been reported. Of course, it is to mention that angiography could detect it.
Pregnancies following embolization are reported to have included a series of known AVMs, although long-term reproductive sequelae are not yet clear. However, the embolization process itself carries potential morbidity including infection, neurological damage, and bladder necrosis (
10). Hysterectomy is mentioned as the only treatment if bleeding is intractable despite the available managements, as mentioned above, and hemodynamic instability also makes interventional radiology unsafe.
One of the uncommon reasons of secondary postpartum hemorrhage is uterine artery pseudoaneurysm, which can cause a life-threatening situation. Management should be multidisciplinary and the gold standard for treatment and diagnosis is through interventional radiology.