Classification of obstetric hemorrhage and clinical stages of shock
The body of a pregnant woman is able to maintain blood pressure for a long time despite a decrease in circulating blood volume (CBV). For this reason, symptoms of peripheral blood circulation disorders require immediate evaluation.
The severity of the condition is assessed according to four classes of blood loss (calculations are given for a body weight of 60 kg and a CBV of 6000 ml):
- Class 1 (up to 1000 ml / less than 15% of CBV): signs of shock are absent, hemodynamic parameters and diuresis are normal, shock index (SI) is 0.5–0.7.
- Class 2 (1000–1500 ml / 15–25% of CBV): mild shock (stage I). Characterized by a feeling of cold, shortness of breath, unexplained anxiety, tachycardia (up to 100 bpm), tachypnea (over 20 bpm), a drop in pulse pressure below 30 mm Hg, and an SI of 0.85–1.0. The capillary refill time exceeds 2 seconds.
- Class 3 (1500–2100 ml / 25–35% of CBV): moderate shock (stage II). Pronounced hypotension (systolic BP 80–100 mm Hg), tachycardia 100–120 bpm, SI 1.0–1.5, oliguria, cold clammy skin, and agitation.
- Class 4 (over 2100 ml / over 35% of CBV): severe shock (stage III). Systolic BP less than 60–80 mm Hg, heart rate 120–160 bpm, SI greater than 1.5, lethargy or sopor, anuria. There is a risk of circulatory collapse.
Infusion-transfusion therapy and resuscitation measures
Care for massive hemorrhage is provided concurrently with bleeding cessation according to the ABC protocol. This will require securing venous access with at least two large-bore catheters (14–16 G), urinary bladder catheterization, pulse oximetry, ECG monitoring, and strict blood loss accounting.
The volume and composition of infusion-transfusion media are distributed depending on the volume of blood lost:
| Parameter / Drug | Degree 1 | Degree 2 | Degree 3 | Degree 4 |
|---|---|---|---|---|
| Volume of blood loss | Up to 1000 ml | 1000–1500 ml | 1500–2100 ml | Over 2100 ml |
| Crystalloids | 3 times the blood loss | 2000 ml | 2000 ml | 2000 ml |
| Colloids (6% HES or 4% gelatin) | — | 500–1000 ml | 1000–1500 ml | 2000 ml |
| Fresh frozen plasma | — | — | 12–15 ml/kg | 12–15 ml/kg or more |
| Packed red blood cells | — | — | 250–500 ml (at Hb <60–70 g/L) | 500 ml or more |
| Autologous blood transfusion | — | — | Blood reinfusion | Blood reinfusion |
Surgical tactics for placenta accreta and vasa previa
During surgical delivery of patients with placenta accreta (Placenta accreta), modern organ-sparing tactics have been established, implemented by a multidisciplinary team involving an angiosurgeon and a transfusiologist.
Stages of organ-sparing surgery:
- Surgical access: performing a midline laparotomy, a low transverse or classical cesarean section is carried out.
- Extraction of the fetus: the fetus is extracted through an incision in the uterine fundus without damaging the placenta. The umbilical cord is transected and its remnant is placed into the uterine cavity, after which the incision is sutured.
- Temporary balloon occlusion: catheters are inserted via the femoral arteries to the aortic bifurcation and balloons are inflated up to 4 atm for 10–20 minutes. Contraindications: hemodynamic instability, stage II–III shock, intra-abdominal hemorrhage.
- Resection and metroplasty: the area of the uterus with the invasive placenta is excised en bloc within healthy tissues followed by reconstruction of the uterine wall.
If placenta accreta is detected during manual removal in the third stage of labor, the manipulation must be immediately stopped, laparotomy performed, internal iliac artery ligation or balloon occlusion carried out with excision of the defect.
Rupture of unprotected vasa previa (Vasa previa) with velamentous cord insertion (Insertio velamentosa) requires emergency cesarean section.
Briefly: answers to topical questions
What are the main etiological causes of postpartum hemorrhage according to the "4Ts" rule?
Among the etiological causes of postpartum hemorrhage according to the "4Ts" rule, two categories are directly named in the materials, and tone abnormalities and tissue retention are also described.
- "Trauma" — lacerations of the soft birth canal and uterus.
- "Thrombin" — hemostasis disorders.
- Uterine tone disorders — hypotonia (reversible decrease in tone) and atony (irreversible loss of tone).
- Retained products of conception — retention of the placenta or fetal membranes in the uterine cavity, preventing its normal contraction.
What uterotonic drugs and in what dosages are used as first-line therapy for hypotonic hemorrhage?
To stimulate myometrial contractility and stop hypotonic hemorrhage, the following uterotonic drugs are used:
- Oxytocin (Oxytocinum) — administered intravenously at a dose of 5 IU in 500 ml of isotonic sodium chloride solution.
- Carbetocin (Carbetocinum) — used at a dosage of 1 ml intravenously slowly.
- Misoprostol (Misoprostolum) — prescribed at a dose of 800–1000 mcg per rectum once.
Also, Ergometrine (an ergot alkaloid) can be used to stop hypotonic hemorrhage in the early postpartum period, although its exact dosage is not specified in the sources.
Formula for the shock index (SI = HR / SBP): "The HIGHER the pulse and the LOWER the systolic blood pressure, the HIGHER the index and the MORE SEVERE the shock" (normal 0.5–0.7; mild 0.85–1.0; moderate 1.0–1.5; severe >1.5).
Class and exam questions
Why do signs of shock in pregnant women appear later than in non-pregnant women?
Pregnant women have pronounced compensatory mechanisms that allow stable hemodynamics to be maintained for a long time even with significant loss of circulating blood volume.
What should an obstetrician do if placenta accreta is discovered during manual removal?
The attempt at manual removal must be stopped immediately. Urgent laparotomy, internal iliac artery ligation, or balloon occlusion with excision of the placenta accreta area is indicated.
What are the contraindications to temporary iliac artery balloon occlusion?
This procedure is contraindicated in grade II–III hemorrhagic shock, hemodynamic instability, and suspected intra-abdominal hemorrhage.
What else to study on this topic
- Technique of temporary balloon occlusion of the common iliac arteries
- Diagnosis of Vasa previa using ultrasound and color Doppler mapping
- Signs of intraoperative detection of placenta accreta into a uterine scar
- Indications for delayed placental removal in the absence of conditions for angiographic hemostasis
- Procedure and interpretation of the capillary refill test
Master the entire topic in the "Obstetrics and Gynecology" course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Obstetric Hemorrhagic Shock" and 973 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 21 video lessons on the subject
Other topics in the "Obstetrics" section
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.