What is the treatment for hyperemesis gravidarum?

Treatment of Hyperemesis Gravidarum

The treatment of hyperemesis gravidarum follows a stepwise approach, beginning with first-line antiemetics such as doxylamine/pyridoxine and phenothiazines, progressing to second-line agents like metoclopramide and ondansetron, and utilizing corticosteroids for refractory cases, alongside appropriate fluid and electrolyte replacement. 1

Definition and Clinical Presentation

• Hyperemesis gravidarum (HG) is characterized by intractable nausea and vomiting during pregnancy, resulting in dehydration, weight loss ≥5% of pre-pregnancy weight, and ketonuria, affecting 0.3-2% of pregnancies 1
• Symptoms typically begin before week 22 of gestation, with resolution in >50% of patients by week 16 and in 80% by week 20, though 10% may experience symptoms throughout pregnancy 2
• HG is associated with elevated liver enzymes in 40-50% of cases, electrolyte imbalances, and potential nutritional deficiencies 2

Initial Assessment

• Evaluate for signs of dehydration (orthostatic hypotension, decreased skin turgor, dry mucous membranes) 2
• Check for malnutrition, neurologic signs of vitamin deficiencies, and electrolyte abnormalities 1
• Laboratory evaluation should include liver function tests, electrolyte panel, and urinalysis for ketonuria 1
• Abdominal ultrasonography helps detect multiple or molar pregnancies and rule out hepatobiliary, vascular, or renal causes of symptoms 2

Treatment Algorithm

First-Line Management

• Immediate intravenous fluid resuscitation to correct dehydration 1
• Thiamine supplementation (100 mg daily for minimum 7 days, followed by 50 mg daily maintenance) to prevent Wernicke's encephalopathy 2
• First-line pharmacologic treatments include:
  • Doxylamine/pyridoxine combination 2, 1
  • Phenothiazines (chlorpromazine, prochlorperazine, promethazine) 2, 1
  • Cyclizine 2

Second-Line Management

• If first-line treatments are ineffective, progress to:
  • Metoclopramide (similar efficacy to promethazine with fewer side effects) 2
  • Domperidone 2
  • Ondansetron (use on case-by-case basis, especially before 10 weeks of pregnancy) 2

Third-Line Management

• For refractory cases:
  • Corticosteroids 2, 3
  • Alternative pharmacotherapeutics like mirtazapine, olanzapine, and gabapentin may be considered 3
  • Enteral or parenteral nutrition for prolonged cases with ongoing weight loss 3

Special Considerations

• Monitor for QT interval prolongation with ondansetron, particularly in patients with electrolyte abnormalities 1
• Drug-induced extrapyramidal adverse effects may occur with phenothiazines and metoclopramide 2
• Persistent liver chemistry abnormalities despite symptom resolution should prompt investigation for another etiology 1

Monitoring and Follow-up

• Regular assessment of hydration status and electrolyte balance 1
• Fetal growth monitoring, especially with insufficient gestational weight gain 1
• Educate patients about the high recurrence risk (40-92%) in subsequent pregnancies 1

Complications

• Untreated HG is associated with low birth weight, small for gestational age infants, and premature delivery 2, 1
• Severe nutritional deficiencies can lead to significant maternal morbidity if not addressed 3
• Thiamine deficiency can lead to Wernicke's encephalopathy, a serious neurological complication 1, 4

Non-Pharmacological Approaches

• Dietary modifications including small, frequent, bland meals, high-protein and low-fat meals 1
• Avoidance of specific food triggers and strong odors 1
• Ginger supplementation has shown some benefit 5

The management of hyperemesis gravidarum requires a comprehensive approach with prompt intervention to prevent complications and improve maternal quality of life and pregnancy outcomes.