How is hypotension managed in pregnancy?

Management of Hypotension in Pregnancy

For hypotension in pregnancy, prioritize left lateral positioning and adequate hydration as first-line interventions, with intravenous fluid boluses for acute symptomatic cases, while carefully monitoring to avoid excessive treatment that could harm the fetus. 1

Initial Assessment and Positioning

Measure blood pressure after 5 minutes of sitting or lying, then repeat at 1 and/or 3 minutes after standing to assess for orthostatic hypotension, which is more common in pregnancy due to increased blood volume. 1

Immediate Positional Management

• Left lateral decubitus positioning is critical to relieve inferior vena cava compression and improve venous return, particularly after 20 weeks gestation when the gravid uterus can compress the inferior vena cava and impede venous return. 2, 1
• Manual left lateral uterine displacement effectively relieves aortocaval pressure in patients with hypotension. 2
• Avoid prolonged supine positioning, as aortocaval compression can occur for singleton pregnancies starting at approximately 20 weeks gestational age or when fundal height is at or above the umbilicus. 2, 1

Non-Pharmacologic Management

Hydration and Volume Support

• Adequate oral hydration is essential to maintain intravascular volume and prevent hypotension throughout pregnancy. 1
• Compression stockings can improve venous return and reduce hypotension risk. 1
• Maintaining adequate hydration throughout pregnancy helps prevent hypotension and improve fetal outcomes. 1

Acute Symptomatic Hypotension

• Intravenous fluid boluses should be used to treat acute symptomatic hypotension. 1
• For cesarean delivery under spinal anesthesia, crystalloid coloading (administered just after intrathecal injection) is more effective than preloading, reducing hypotension incidence from 83% to 53%. 3
• Hydroxyethyl starch (HES) preloading or coloading is more consistently effective than crystalloid preloading for preventing spinal-induced hypotension during cesarean delivery. 4

Pharmacologic Management

Vasopressor Use

• Vasopressors may be considered in severe cases but should be used with caution. 1
• Ephedrine is FDA-approved for hypotension in pregnancy, though cases of potential metabolic acidosis in newborns have been reported with maternal ephedrine exposure (umbilical artery pH ≤7.2). 5
• Monitoring of the newborn for signs and symptoms of metabolic acidosis may be required after ephedrine use. 5

Special Anesthesia Considerations

• Pre-hydration with intravenous fluids before regional anesthesia can help prevent hypotension. 1
• Left lateral tilt positioning during cesarean section helps prevent hypotension. 1
• Prophylactic vasopressor regimens should always be added to fluid loading methods, as fluid loading alone is not completely effective at preventing hypotension during spinal anesthesia. 4

Medication Adjustment in Hypertensive Patients

A critical pitfall is iatrogenic hypotension from excessive antihypertensive therapy. 1

• Antihypertensive drugs should be reduced or ceased if diastolic blood pressure falls below 80 mmHg. 1
• Target diastolic blood pressure should be 85 mmHg in office settings, with systolic blood pressure maintained at 110-140 mmHg. 1
• During labor and delivery in women with hypertensive disorders, antihypertensive treatment should be continued to keep SBP <160 mmHg and DBP <110 mmHg. 2

Monitoring and Fetal Considerations

Maternal Monitoring

• Regular blood pressure monitoring throughout pregnancy is essential to detect and manage hypotension. 1
• Assessment of fetal growth and well-being with ultrasound is necessary if persistent hypotension is present. 1

Fetal Impact

• Untreated maternal hypotension can decrease uterine blood flow, potentially resulting in fetal bradycardia and acidosis. 5
• Historical studies suggest that untreated maternal hypotension (BP ≤110/65 mmHg) is associated with significantly smaller neonates, higher rates of fetal dystrophy, and reduced placental perfusion. 6, 7
• Treatment of maternal hypotension improves placental perfusion rates and fetal outcomes. 6, 7

Critical Pitfalls to Avoid

• Do not delay positional interventions (left lateral positioning) while pursuing other treatments. 2
• Avoid crystalloid preloading alone for cesarean delivery under spinal anesthesia, as it is clinically ineffective. 4
• Do not over-treat hypertensive pregnant women, as iatrogenic hypotension poses risks to both mother and fetus. 1
• Avoid prolonged standing or lying supine, particularly after 20 weeks gestation. 1
• Regular prenatal care is essential to monitor maternal and fetal well-being and prevent adverse outcomes. 1