Uterine Artery Embolization (UAE) is a specialized, minimally invasive procedure employed to address severe postpartum hemorrhage (PPH), which is excessive bleeding after childbirth. It serves as an important alternative when initial treatments, such as medications or uterine massage, prove insufficient to control the bleeding. The technique involves blocking the arteries that supply blood to the uterus, which can effectively stop the hemorrhage and, in many cases, prevent the need for a hysterectomy.
Understanding Postpartum Hemorrhage
Postpartum hemorrhage is a serious obstetric emergency characterized by excessive blood loss after childbirth. Medically, it is often defined as losing more than 1,000 milliliters of blood within the first 24 hours following delivery. This condition is a significant cause of maternal health complications and mortality worldwide, necessitating prompt and effective medical intervention.
The most frequent cause of PPH is uterine atony, a condition where the uterus fails to contract sufficiently after the placenta is delivered. These contractions are necessary to compress the blood vessels at the site where the placenta was attached. Other causes include trauma to the cervix, vagina, or uterus during delivery; retention of placental tissue within the uterus; or underlying disorders of blood clotting. Because of the potential for rapid blood loss, healthcare providers first attempt to manage PPH with conservative measures, such as administering medications that stimulate uterine contractions and performing uterine massage.
The Uterine Artery Embolization Procedure
When initial treatments for postpartum hemorrhage are not successful, uterine artery embolization may be considered for women who are in a stable hemodynamic condition. This procedure is performed by an interventional radiologist, a specialist in minimally invasive, image-guided treatments. The goal of UAE is to selectively block the blood vessels supplying the uterus, thereby stopping the hemorrhage while preserving the organ itself as an effective alternative to a hysterectomy.
The procedure begins with the patient receiving a local anesthetic and sedation. The interventional radiologist then makes a small puncture in the femoral artery, located in the groin, to insert a thin, flexible tube called a catheter. Using real-time X-ray imaging, known as fluoroscopy, the radiologist carefully guides the catheter through the arterial system into the uterine arteries, the primary vessels that provide blood to the uterus.
Once the catheter is correctly positioned in the arteries supplying the bleeding sites, the radiologist injects tiny particles called embolic agents. The particles travel into the smaller arterial branches and create a blockage that stops blood flow to the bleeding area. This process is usually performed on both the left and right uterine arteries to ensure the hemorrhage is fully controlled.
Expected Outcomes and Potential Risks of UAE
Uterine artery embolization has a high rate of success in controlling postpartum hemorrhage, with clinical success rates of over 90%. A significant benefit of the procedure is its ability to preserve the uterus, which avoids a hysterectomy and maintains the possibility of future pregnancies. Compared to major surgery, UAE is minimally invasive, generally resulting in a shorter hospital stay and a quicker recovery period for the mother.
Despite its high success rate, UAE is associated with potential risks and complications. Some women may experience post-embolization syndrome, which involves symptoms like pelvic pain, fever, and nausea; these symptoms are typically managed with medication. More serious, though less common, complications can include infection or non-target embolization, where the embolic agents travel to other parts of the body, causing tissue damage. Uterine necrosis, or tissue death, is a rare but severe complication.
For women who have undergone UAE and wish to have more children, there is evidence of increased risks in subsequent pregnancies. These can include a higher likelihood of placental problems, such as placenta accreta, where the placenta attaches too deeply into the uterine wall, and a greater chance of preterm birth. The risk of recurrent PPH in a future delivery is also higher for these women.
Alternative Treatments for Severe Postpartum Hemorrhage
When uterine artery embolization is not available, is not appropriate for the patient, or fails to control the bleeding, other interventions are necessary. These treatments are typically more invasive and surgical in nature.
One surgical approach involves placing compression sutures, such as the B-Lynch suture, which physically compress the uterus to control bleeding. Another option is uterine artery ligation, where a surgeon directly ties off the uterine arteries to stop blood flow. In some situations, a Bakri balloon may be inserted into the uterus; it is then filled with saline to create internal pressure against the bleeding surfaces.
If these methods are unsuccessful and the bleeding remains life-threatening, the definitive treatment is a hysterectomy, the surgical removal of the uterus. This procedure will permanently stop the bleeding but also results in the inability to carry future pregnancies.