1. Data and methods 1.1 Clinical data From March 2007 to June 2009, 36 cases of emergency obstetric and gynecological bleeding, aged 19-58 years, with an average age of 29±2.6 years, were admitted to our department after conservative treatment. There were 23 cases of obstetric bleeding, including 2 cases of bleeding after vaginal delivery, 1 case of bleeding after cesarean section, 2 cases of bleeding after abortion, 8 cases of cervical pregnancy bleeding, 10 cases of postpartum placenta implantation or residual; 13 cases of gynecologic cancer bleeding, including 10 cases of cervical cancer bleeding, 1 case of choriocarcinoma bleeding, and 2 cases of erosive gravida bleeding. The cumulative bleeding volume ranged from 600 to 1500 ml, with an average bleeding volume of 1100 ml, and 8 cases were in shock at the time of intervention.1.2 Methods Patients were treated with fluid replacement and cardiac monitoring, etc. A modified Seldinger technique was used to puncture the right femoral artery, and guide wires and catheters were introduced through the puncture needle. The catheter tip was adjusted to enter the internal iliac artery on both sides for digital subtraction angiography (DSA). When the bleeding vessel is confirmed, the target vessel is super-selectively cannulated and embolized with embolic agents such as gelatin sponge particles. If the condition is critical or the catheter cannot enter the target vessel, the embolic agent is slowly released at low pressure using contrast tracing in the internal iliac artery and stopped after the embolization is satisfactory. The effect of embolization was reviewed by separate imaging, and after confirming no bleeding, the tube was removed and pressure bandaged. 2. RESULTS 2.1 DSA imaging showed focal or diffuse contrast spillage in 12 cases on DSA imaging. The remaining 24 patients showed the same contrast performance as the primary imaging. Malignant tumors such as cervical cancer and choriocarcinoma showed varying degrees of thickening and tortuosity of uterine arteries, proliferation of branch vessels, vascular encirclement and pushing displacement, tumor staining, and invasion of adjacent organs and tissues. In addition to thickening and hyperplasia of uterine arteries and their branches, postpartum hemorrhage also shows enlarged, irregular and delayed emptying of uterine contours in the parenchymal phase of the imaging. In trophoblastic tumors, abnormally dilated blood sinuses and abundant arteriovenous shunts were also seen in the lesion area. In all patients, only the uterine artery or internal iliac artery trunk was preserved after embolization. 2.2 Embolization treatment and embolization results All patients had bilateral target vessels embolized, 31 patients had bilateral uterine artery embolization and 5 patients had bilateral internal iliac artery embolization, and the operation time ranged from 30 to 63 minutes, with an average of 45 minutes. 22 patients had immediate hemostasis after embolization. 14 patients had significantly reduced bleeding after embolization, and the bleeding stopped after 2 to 5 d of symptomatic treatment. 2.3 Postoperative side effects and complications After TAE, patients experienced different degrees of pain in the lower abdomen, buttocks and lower extremities, which disappeared within 3-7 days after surgery with symptomatic treatment. The average temperature of postoperative patients was 37.8℃, generally not more than 38.3℃, and lasted for 5-10 days to normal. Gastrointestinal reactions such as mild nausea, vomiting and loss of appetite were observed in those with arterial perfusion chemotherapy and resolved after symptomatic treatment. No serious complications were found in all cases. Except for 5 menopausal patients, the rest of the patients resumed normal menstruation about 1-1.5 months after embolization.3. Discussion Emergency obstetric and gynecological bleeding is very common in clinical practice, and the common causes include postpartum hemorrhage, placental implantation, ectopic pregnancy rupture, post-abortion hemorrhage, and tumor hemorrhage. In the past, obstetrical and gynecological bleeding was mostly treated conservatively with drugs and transvaginal or hysteroplasty gauze to stop bleeding. Internal iliac artery ligation is not only technically difficult, but also has a hemostatic efficiency of only 42% [1]. Total hysterectomy or subtotal hysterectomy is effective in stopping bleeding, but in young, infertile or fertile patients, the procedure causes loss of reproductive function and has serious physical and psychological effects on the patient, which is often difficult to accept. These patients are often in a state of hemorrhagic shock and have difficulty with anesthesia and surgery. Studies have shown that the uterus is not only a reproductive organ, but also has endocrine functions, and after hysterectomy, menopause comes early, aging is accelerated, and the age of onset of coronary heart disease is advanced [2]. Since Brown first reported the treatment of postpartum hemorrhage by transarterial embolization in 1979, internal iliac artery embolization (IAE) or bilateral uterine artery embolization (UAE) have been performed and reported in China and abroad. to treat emergency obstetric and gynecological bleeding. Ni Cai-Fang et al [3] and Jin Hai-Ying et al [4] reported very good treatment results using internal iliac artery embolization or uterine artery embolization for postpartum hemorrhage. Yin [5] et al. used UAE to treat 16 cases of obstetrical and gynecological refractory hemorrhage, and all patients had satisfactory hemostasis after the procedure.TAE has low requirements for patients, except for patients with DIC combined with bleeding from other organs, patients with extremely unstable vital signs and those who should not be moved, etc. TAE is not only simple, less invasive, with rapid and definite results, avoiding painful open abdomen, but also preserving the uterus, and has gradually become 3.1 Embolization technique As obstetrical and gynecological hemorrhage is fierce and critical, rapid hemostasis and rescue of patient’s life are crucial, and rapid and accurate intubation is the key to treatment. The operation should be completed by physicians who are relatively skilled in catheterization, so as to minimize the operation time and better rescue the patients. Most of the embolizations in our department for obstetrical and gynecological bleeding are completed within 1h, which has the purpose of rapid hemostasis. Determining the target vessel to be embolized is the first step of embolization treatment. Since most obstetrical and gynecological hemorrhages are internal iliac artery branches, most of them are uterine artery branches, which can be clarified by DSA imaging of internal iliac arteries bilaterally, and the phenomenon of contrast spillage can be seen during the active period of hemorrhage. Selective intubation should be performed with bilateral internal iliac artery embolization, preserving the capillaries and anastomotic branches of the organ, as the pelvic organs have abundant collateral circulation and extensive arterial anastomotic branches exist, and as long as the embolic agent is properly selected not to have serious complications such as organ necrosis [6]. If the DSA angiogram is in the interhemorrhagic phase, the angiogram is often negative. For a negative DSA angiogram with clear symptoms of hemorrhage, arterial embolization is essential, which can be performed when the catheter enters the internal iliac artery and avoids the superior gluteal artery. The embolization should be performed by slowly releasing the embolic agent at low pressure and using the “siphon” effect to embolize the bleeding vascular bed, which can avoid the return of embolic agent to the external iliac artery to embolize the terminal vessels of the lower limbs after the pressure of the target vessel increases, and also avoid the occurrence of “pseudo-embolism”. Domestic scholars have different views on whether to perform bilateral uterine artery embolization. Jin Haiying et al [4] concluded that although percutaneous uterine artery embolization has minimal tissue ischemia and generally does not affect fertility, it should be carefully considered when embolizing both uterine arteries in primiparous women and patients with the need for re-birth. As the uterine blood supply is clearly unilateral, the ipsilateral uterine body is supplied by one uterine artery under normal conditions, and the abundant traffic branches in the middle of the uterine body are usually mostly closed, but in the case of inability of the contralateral uterine artery to supply blood, the traffic branches open and supply the contralateral uterine body, so embolization of only one uterine artery or internal iliac artery is prone to failure. In one report [7], embolization of the internal iliac artery alone was used to treat postpartum hemorrhage, and rebleeding occurred after the procedure. In the author’s opinion, it is necessary to use bilateral uterine artery or internal iliac artery embolization for rapid hemostasis of obstetrical and gynecological hemorrhage in order to avoid delaying the disease. 3.2 The choice of embolization material is varied, and the literature [8] reports that gelatin sponge, silk wire segment, spring steel coil, polyvinyl alcohol, etc. are available. According to the time of recanalization after embolization, they are divided into short-acting, medium-acting and long-acting embolic agents. The commonly used embolic agents in clinical practice are gelatin sponges, PVA pellets, real silk wire segments, spring steel coils, etc. Fresh gelatin sponge particles are soluble and transient embolic substances, which can be absorbed 2 to 3 weeks after embolization and the blood vessel is reopened, and they belong to short- and medium-acting embolic agents, while polyvinyl alcohol particles (PVA), silk wire segments and spring steel rings belong to long-acting embolic agents. The choice of embolic agent should be related to the patient’s age, underlying disease and embolization purpose. Gelatin sponge is the most widely used embolic agent in clinical practice, which is easy to obtain, and the uterine artery can be recanalized and blood supply restored 2-3 weeks after surgery, which can preserve and restore the patient’s reproductive function [9]. Non-permanent embolic agents, such as gelatin sponges, should be preferred in young women whenever possible to ensure that their utero-ovarian function is restored as much as possible after hemostasis and to reduce associated adverse effects or complications (e.g. premature ovarian failure) . In tumorigenic hemorrhage, where recurrence is more likely, PVA pellets or gelatin sponges with silk segments are often used to achieve permanent embolization. Spring steel ring embolization of larger arteries is likely to cause re-bleeding due to the establishment of collateral circulation or to fail to achieve effective embolization, therefore, mainly for those with severe vascular injury, permanent reinforced embolization can be performed with stainless steel ring on top of gelatin sponge embolization [5]. For postpartum, trauma and other non-neoplastic bleeding using gelatin sponge can achieve good hemostatic effect, stainless steel ring embolization is not appropriate [10], and liquid embolic agents such as anhydrous alcohol are generally not used [4].3.3 Side effects and complications All patients had different degrees of hypothermia, fatigue, fatigue, nausea, vomiting, lower abdominal pain and other manifestations of post-embolization syndrome after embolization, and the symptoms disappeared after symptomatic treatment. Although transcatheter embolization of bilateral uterine arteries or internal iliac arteries is considered safe by clinicians, various complications can still occur. Ke Xuemei et al [11] observed 201 patients with pelvic disorders undergoing pelvic target vessel embolization and found that 9 cases occurred after serious complications, with an incidence of 4.5%. Among them, there were 4 cases of hip ischemic necrosis, 2 cases of urinary frequency, urgency, painful urination and hematuria, 2 cases of lower limb numbness and sensory disturbance, 1 case of purulent and bloody vaginal discharge, and 1 case of severe perineal edema. The causes of complications were considered to be mainly related to the indications and improper selection of embolic agent materials. In our group, there were no serious complications after embolization in 36 patients. Reasonable selection of embolic agent and slow injection of embolic material under fluoroscopic surveillance during embolization to avoid excessive embolization leading to embolic material reflux were important reasons. Since the ovarian blood supply comes from the ovarian artery and the superior branch of the uterine artery, theoretically vascular interventions can affect the blood supply of the ovarian artery, thus affecting the function of the ovary leading to menstrual disorders. Zhu Bin [6] et al. used multi-row spiral CT arterial vascular reconstruction to understand the uterine artery blood supply after internal iliac artery embolization and found that the uterus was able to obtain arterial blood supply to maintain physiological needs through either compensatory or (and) partially or completely open uterine artery or other small side branches after embolization of the ovarian artery, and the longest postoperative follow-up of patients was 26 months, and several hormone tests were normal, indicating that this method does not have a serious impact on uterine and ovarian The longest postoperative follow-up was 26 months, and several hormone tests were normal, indicating that this method does not cause serious effects on uterine and ovarian function. Wang Jinjiang et al [12] showed that no significant organic damage to the uterus, especially to the basal endometrium, occurred after interventional treatment, and that the effects on ovarian function were either non-existent or transient, mild and reversible. The recovery of menstruation in our patients after interventional treatment was similar to the above reports, and the menstrual status of patients was not significantly affected after interventional treatment. In conclusion, emergency transcatheter arterial embolization has the advantages of simple operation, rapid hemostasis, effectiveness and few complications, and preservation of the uterus, which is a more ideal treatment method for emergency obstetrical and gynecological bleeding when conservative treatment is ineffective.