Primary postpartum hemorrhage is defined as bleeding more than 1000 mL or anemia-related symptoms and signs within 24 hours of cesarean section or vaginal delivery. The most common cause of this type of postpartum hemorrhage is uterine tonil, accounting for about 70%, and its occurrence mechanism is that the uterus does not contract sufficiently after delivery, resulting in continuous opening of the blood vessels of the uterine wall and bleeding. Other causes include remnants of placental and fetal tissue (about 15%), damage to the genital tract (about 10%), in addition to coagulation dysfunction, uterine inversion, and uterine arteriovenous malformationsand other rare situations. From the perspective of childbirth-related risk factors, the use of forceps or vacuum-assisted vaginal delivery, episiotomy, placental abruption, stillbirth, etc. will increase the risk of primary postpartum hemorrhage.

Secondary postpartum hemorrhage is excessive bleeding that occurs between 24 hours and 12 weeks after delivery. Common causative factors include placental tissue retention, endometritis (infection-related), hereditary coagulation disorders (eg, von Willebrand disease, hemophilia A/B, coagulation factor deficiency, platelet abnormalities, etc.), uterine arteriovenous malformations, and placental attachment site incomplete That is, the spiral artery in the myometrium where the placenta is originally attached continues to dilate and does not contract normally.

For women with vaginal delivery, first-line management measures include active management of the third stage of labor (promoting rapid delivery of the placenta with moderate traction of the umbilical cord), intravenous infusion of inotropin, bladder drainage, Bilateral uterine massage, which is usually effective in relieving most postpartum hemorrhage.

If the bleeding does not resolve rapidly after the above treatment, further evaluation is required: uterine tone is judged by biplicary palpation, and uterine contraction is checked for atony; Visual examination was used to evaluate the cervix and vagina to confirm the presence of lacerations; Perform abdominal or pelvic ultrasound examination to assess the uterine and endometrial condition, where the thickness of the endometrium exceeds 2cm, which highly indicates the presence of placental tissue residue; In addition, trauma ultrasound focused evaluation can assist in determining the presence of intra-abdominal hemorrhage.

Laboratory evaluations need to be carried out urgently, including complete blood count (to assess blood loss), biochemical index testing, prothrombin time/international normalized ratio, Partial thromboplastin time, fibrinogen level determination, and blood group identification and cross-matching test (in preparation for transfusion). As a point-of-care diagnostic technology, thromboelastography can evaluate the formation, strength and stability of blood clots during coagulation in real time, and provide guidance for the selection of blood products.

Patients with postpartum hemorrhage need to undergo close hemodynamic monitoring, establish intravenous access according to the needs of the condition, and infuse intravenous fluids and blood products. The optimal management of postpartum hemorrhage relies on multidisciplinary teamwork, including obstetricians, anesthesiologists, hematologists, and critical care physicians. For medical institutions without relevant specialty diagnosis and treatment, if the bleeding cannot be controlled by standard interventions, patients need to be transferred to a higher-level medical center in a timely manner.

Medications and physical therapy For bleeding caused by uterine atony, tocotonics such as oxytocin (30U dissolved in 500mL liquid intravenous infusion or 10U intramuscular) are used misoprostol (800 μg rectal administration), methylergometrine (0.2 mg intramuscular, once every 2 hours, use with caution in hypertensive patients).carboprost (0.25mg intramuscular, once every 15 minutes, maximum dose of 8 doses, use with caution in patients with asthma and other lung diseases), denoprostone (20μg rectal administration), etc.; At the same time, it can be combined with uterine massage to enhance the effect.

For intrauterine hemostasis, uterine tamponade (eg, uterine balloon, 50-500 mL fluid injection), uterine gauze strip tamponade, or uterine suction device may be used ； For cervical or vaginal lacerations, resorbable delayed sutures are used to repair, and cervical and vaginal tamponade can be performed when repair is not possible.

Interventional and surgical treatment For patients who do not respond to drugs and physical therapy, referral to the Department of Interventional Radiology for uterine artery embolization may be considered; If the bleeding persists or does not meet the conditions for embolization treatment, surgical intervention is required, including laparoscopic uterine suturing, utero-ovarian vascular ligation, anterior iliac artery ligation, etc.; If none of the above measures fail, hysterectomy can be used as a last resort to stop bleeding, but it should be noted that this surgery is associated with a higher risk of complications, such as the incidence of urinary system damage can reach 18%.

Use of blood products and hemostatic drugs For patients with postpartum hemorrhage with hypotension or tachycardia, homotype concentrated red blood cells, fresh frozen plasma and platelets can be transfused in a 1:1:1 ratio; Compared with the fixed-ratio transfusion regimen, blood transfusion under the guidance of thromboelastography can increase cryoprecipitation and the use of antifibrinolytic drugs, which may reduce the risk of transfusion-related acute lung injury, cardiac insufficiency and other complications.

In addition, tranexamic acid (1 g intravenously infusion over 10 minutes, repeated administration after 30 minutes if bleeding does not stop) can be used to stop bleeding, according to a study of 20,060 patients with postpartum hemorrhageThe bleeding-related mortality rate was lower in the tranexamic acid group than in the placebo group(1.5% vs. 1.9%, hazard ratio 0.81, 95% confidence interval 0.65 to 1.00), and no adverse events were increased; among them, the difference in bleeding-related mortality was more significant in those who took the drug within 3 hours after delivery (1.2% vs. 1.7%, hazard ratio 0.69, 95% confidence interval 0.52-0.91, P=0.008).

The initial evaluation of secondary postpartum hemorrhage includes physical examination, hemodynamic stability assessment, and quantification of bleeding volume; Transvaginal ultrasound examination is required to determine whether there are uterine abnormalities such as placental tissue residue, placental attachment insufficiency, uterine arteriovenous malformations, and pseudoaneurysms.

When placental tissue residue is confirmed or highly suspected, negative pressure hysterosupration is recommended for removal; For patients with endometritis (manifested by postpartum fever, uterine tenderness, or foul-smelling vaginal discharge), intravenous antibiotics (eg, penicillin or first-generation cephalosporins combined with aminoglycosides) are indicated; Uterine balloon tamponade can temporarily control bleeding caused by placental involution insufficiency, and persistent or severe secondary postpartum hemorrhage may require uterine artery embolization or hysterectomy.

Regular prenatal examination can identify high-risk groups for postpartum hemorrhage through medical history, laboratory tests, and imaging evaluation. Pregnancy anemia needs to be corrected by oral or intravenous iron supplementation. Pregnant women with prenatal placental abnormalities (eg, placenta previa, placenta accreta spectrum disorders) should be transferred to a medical center with relevant surgical specialists for delivery.

Obstetric hemorrhage simulation training can improve the clinical team's compliance with the management plan, shorten the initiation time of definitive interventions, improve the efficiency of team communication, and improve the effectiveness of postpartum hemorrhage treatment.

As an important obstetric emergency that causes maternal death, the effective management of postpartum hemorrhage relies on the organic combination of early identification, stabilization and standardized treatment, and the treatment methods include the use of uterotonics, uterine massage, mechanical hemostatic devices, uterine artery embolization and surgical intervention, etc., and multidisciplinary collaboration is the key to ensuring the treatment effect.

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