What is the treatment for Hyperemesis gravidarum?

Treatment for Hyperemesis Gravidarum

The treatment of hyperemesis gravidarum requires a stepwise approach beginning with rehydration, correction of electrolyte abnormalities, thiamine supplementation, and anti-emetic therapy, with escalation to more aggressive interventions for refractory cases. 1

Definition and Clinical Presentation

Hyperemesis gravidarum (HG) is a severe form of nausea and vomiting in pregnancy characterized by:

• Persistent vomiting with weight loss ≥5% of prepregnancy body weight
• Dehydration and ketonuria
• Occurs in 0.3-2% of pregnancies 1
• Typically begins in the first trimester, with symptoms resolving by week 20 in approximately 80% of affected women 1

First-Line Management

Non-pharmacological Interventions

• Dietary modifications:
  • Small, frequent, bland meals
  • BRAT diet (bananas, rice, applesauce, toast)
  • High-protein, low-fat meals
  • Avoidance of specific triggers and foods with strong odors 1

Initial Pharmacological Management

1. Vitamin supplementation:

   • Vitamin B6 (pyridoxine): 10-25 mg every 8 hours
   • Thiamine (vitamin B1): 100 mg daily for minimum 7 days, followed by 50 mg daily until adequate oral intake is established (prevents Wernicke's encephalopathy) 1
   • Ginger: 250 mg capsule 4 times daily 1

2. First-line antiemetics:

   • Doxylamine and pyridoxine combination (available in 10 mg/10 mg and 20 mg/20 mg combinations) 1
   • H1-receptor antagonists: promethazine, dimenhydrinate 1

Second-Line Management for Persistent Symptoms

For patients who don't respond to first-line therapy:

1. Metoclopramide: Effective for HG with fewer side effects than promethazine and no increased risk of congenital defects 1

2. Ondansetron: Used primarily for severe cases requiring hospitalization

   • Should be used as second-line therapy
   • Use on case-by-case basis before 10 weeks of pregnancy
   • No association with increased risk of stillbirth, spontaneous abortion, or major birth defects, though some studies report cases of congenital heart defects when given in first trimester 1

Management of Severe HG Requiring Hospitalization

For patients with severe dehydration, electrolyte abnormalities, or significant weight loss:

1. Intravenous hydration and electrolyte correction 1

2. Laboratory monitoring:

   • Electrolytes (note that abnormal liver enzymes occur in ~50% of HG cases) 1
   • Nutritional parameters
   • Urinalysis for ketones

3. Third-line medications for refractory cases:

   • Methylprednisolone: 16 mg IV every 8 hours for up to 3 days, followed by tapering over 2 weeks
     • Reduces rate of rehospitalization
     • Use with caution in first trimester (before 10 weeks) due to possible slight increase in risk of cleft palate 1
   • Alternative agents for refractory cases:
     • Mirtazapine 2, 3
     • Olanzapine 2
     • Gabapentin 2

4. Nutritional support for prolonged cases with ongoing weight loss:

   • Enteral nutrition
   • Parenteral nutrition (as last resort) 2

Special Considerations

Monitoring and Follow-up

• Regular assessment of hydration status
• Weight monitoring
• Electrolyte checks, especially in severe cases
• Psychological support (HG can have significant psychological impact) 4

Complications to Watch For

• Metabolic disorders including hypovolemia and acute kidney injury 5
• Electrolyte disturbances (hyponatremia, hypochloremia, hypokalemia)
• Wernicke's encephalopathy (preventable with thiamine supplementation) 1
• Maternal malnutrition and weight loss

Pregnancy Outcomes

• HG is associated with higher frequency of low birth weight, small for gestational age, and premature delivery 1
• High recurrence risk in subsequent pregnancies 1

Pitfalls and Caveats

1. Don't delay treatment - Early intervention may help prevent progression to severe HG 1

2. Don't forget thiamine supplementation - Essential to prevent Wernicke's encephalopathy, especially before starting IV glucose 1

3. Consider differential diagnoses - Persistent liver chemistry abnormalities despite symptom resolution should prompt investigation for another etiology 1

4. Monitor for complications - HG can lead to severe metabolic abnormalities including acute kidney injury and electrolyte disturbances 5

5. Recognize psychological impact - HG significantly affects quality of life and may require psychological support 4