Makindo Medical Notes

Shock in pregnancy is often under-recognised because physiological changes (↑ plasma volume ~40–50%, ↑ cardiac output, ↓ SVR) can mask hypotension until late. The gravid uterus may cause aortocaval compression when supine, reducing venous return and cardiac output. Priorities are maternal resuscitation first, relief of caval compression, rapid identification of the cause, and urgent obstetric involvement—saving the mother saves the fetus.

🧠 Why it’s different (Pathophysiology)

• ↑ Blood volume and ↑ cardiac output → delayed hypotension despite major haemorrhage.
• ↓ Systemic vascular resistance → warm peripheries may persist despite shock.
• Aortocaval compression (from ~20 weeks) → ↓ preload and cardiac output when supine.
• ↑ O₂ consumption and ↓ functional residual capacity → faster hypoxaemia.

🩸 Common Causes

• Obstetric haemorrhage: ectopic pregnancy, placenta praevia/abruption, uterine rupture, postpartum haemorrhage.
• Sepsis: chorioamnionitis, endometritis, urinary/respiratory sources.
• Thromboembolism: massive PE (pregnancy is a hypercoagulable state).
• Rare: amniotic fluid embolism, anaphylaxis, cardiomyopathy (PPCM).

🔎 Assessment (Do not wait for hypotension)

• ABC with maternal SpO₂ ≥ 95%; look for tachycardia, tachypnoea, confusion, oliguria.
• Position: 15–30° left lateral tilt (or manual uterine displacement) to relieve aortocaval compression.
• IV access ×2; bloods: FBC, U&E, LFTs, CRP, lactate, clotting, G&S/crossmatch, cultures if sepsis.
• Bedside: ECG, ABG/VBG; obstetric ultrasound if bleeding/instability; fetal assessment once mother stabilised.

🛠️ Immediate Management

• High-flow O₂; crystalloid boluses judiciously, early blood products if haemorrhage (activate massive haemorrhage protocol).
• Empirical broad-spectrum IV antibiotics within 1 hour if sepsis suspected.
• Early vasopressors (e.g., noradrenaline) if refractory to fluids, with critical care input.
• Urgent obstetric/surgical control of source: theatre for ectopic/rupture/PPH; interventional radiology if available.
• Continuous maternal monitoring; fetal monitoring when feasible after maternal stabilisation.

🚩 Red Flags (Act Immediately)

• Collapse with abdominal pain or vaginal bleeding at any gestation.
• Persistent hypotension or rising lactate despite fluids/blood.
• Chest pain, hypoxia, syncope → consider PE or AFE.
• Fever with rigors and uterine tenderness → septic shock until proven otherwise.

Cases

• Case 1 — Hypovolaemic Shock (APH): A 32-year-old at 34 weeks presents with heavy painless vaginal bleeding, pallor, tachycardia, and hypotension. Uterus tense and non-tender. Diagnosis: placental abruption with hypovolaemic shock. Plan: ABC resuscitation, large-bore IV access, fluids and blood products, urgent obstetric review, and likely emergency delivery.
• Case 2 — Septic Shock (Chorioamnionitis): A 27-year-old at 29 weeks presents with fever, tachycardia, hypotension, and uterine tenderness. Foul-smelling liquor noted on exam. Diagnosis: chorioamnionitis progressing to septic shock. Plan: Broad-spectrum IV antibiotics, IV fluids, cultures, urgent obstetric involvement, and delivery if maternal/foetal compromise persists.
• Case 3 — Anaphylactic Shock (Labour Ward): A 35-year-old undergoing emergency caesarean develops hypotension, bronchospasm, and generalised urticaria after IV antibiotic prophylaxis. Diagnosis: anaphylaxis. Plan: Call for help, give IM adrenaline 0.5 mg, high-flow oxygen, IV fluids, airway support, and coordinate with obstetric and anaesthetic teams for maternal and foetal safety.