How are physiological changes in pregnancy managed?

Management of Physiological Changes in Pregnancy

Effective management of physiological changes during pregnancy requires a system-based approach that accounts for normal adaptations while monitoring for pathological deviations to optimize maternal and fetal outcomes.

Cardiovascular System Management

• Monitor heart rate increases (10-20 beats/minute) and cardiac output increases (30-50%) that begin around 20 weeks and peak at 32 weeks 1
• Position pregnant women in left lateral tilt during procedures to prevent supine hypotension syndrome and maintain hemodynamic stability 2
• Distinguish normal blood pressure changes (10-15 mmHg decrease by 20 weeks with return to baseline by term) from hypertensive disorders which occur in 6-8% of pregnancies 2, 1
• Recognize that BNP and troponin should remain normal during pregnancy - elevations warrant investigation 1

Respiratory System Management

• Acknowledge normal respiratory changes including:
  • Increased tidal volume (20-40%)
  • Increased minute ventilation (20-40%)
  • Decreased functional residual capacity (10-25%)
  • Increased oxygen consumption (20-33%) 1
• Understand that mild dyspnea is normal but should not be accompanied by oxygen desaturation 1
• Monitor for compensated respiratory alkalosis (arterial CO₂ 28-32 mmHg, bicarbonate 18-21 mEq/L) 1
• Recognize rapid oxygen depletion risk during periods of apnea due to decreased functional residual capacity 1

Hematologic System Management

• Monitor for physiologic hypercoagulability with increased coagulation factors, fibrinogen, and platelet adhesiveness 2
• Implement appropriate thromboprophylaxis for high-risk patients, recognizing increased thromboembolic risk 2
• Note that D-dimer is not recommended for VTE diagnosis due to physiologic elevation 1

Renal and Metabolic Management

• Account for increased renal perfusion and hepatic metabolism when dosing medications 2
• Monitor glucose homeostasis changes and increased cholesterol levels (up to five times normal) 2, 1
• Adjust drug dosing based on altered pharmacokinetics which vary throughout pregnancy 2

Gastrointestinal Management

• Position patients with left lateral tilt during procedures to improve exposure while maintaining hemodynamic stability 2
• Take precautions against pregnancy-associated gastroesophageal reflux which increases aspiration risk during procedures 2

Surgical Considerations

• Schedule elective procedures in early second trimester when possible to minimize miscarriage risk 2
• Use regional anesthesia when appropriate to minimize fetal exposure to medications 2
• Consider laparoscopic approach when feasible (shorter operative times, fewer fetal adverse effects) with:
  • Low intra-abdominal pressure (10-13 mmHg)
  • Limited procedure duration (90-120 minutes)
  • Open introduction technique
  • Experienced surgeon 2

Labor and Delivery Management

• Anticipate significant hemodynamic changes during labor:
  • 15-25% increase in systolic BP during contractions
  • 10-15% increase in diastolic BP during contractions
  • Cardiac output increases (15% in early labor, 25% during stage 1,50% during expulsive efforts)
  • 80% increase in cardiac output early post-partum 2
• Monitor for post-partum complications that may result from physiological changes during pregnancy, including pelvic floor disorders and genitourinary conditions 2

Long-term Considerations

• Recognize that physiological changes during pregnancy can lead to medium and long-term maternal complications including pelvic floor disorders and genitourinary conditions 2
• Provide genetic counseling for women with cardiovascular disease regarding inheritance risk for offspring 2

Medication Management

• Avoid grapefruit juice with medications like nifedipine (increases drug exposure) 3
• Monitor blood glucose carefully when using medications that may affect glucose control 3
• Exercise caution with medication use, recognizing altered pharmacokinetics throughout pregnancy 2

Understanding these physiological adaptations is essential for distinguishing between normal pregnancy changes and pathological conditions, allowing for appropriate management strategies that optimize both maternal and fetal outcomes.