What are the initial management recommendations for Hyperemesis Gravidarum (HG)?

Initial Management of Hyperemesis Gravidarum (HG)

The initial management of hyperemesis gravidarum should focus on preventing dehydration, correcting electrolyte abnormalities, and supporting adequate maternal nutrition through a step-up approach starting with vitamin supplementation and progressing to antiemetics as needed. 1, 2

Definition and Assessment

• HG is characterized by persistent vomiting, weight loss ≥5% of pre-pregnancy weight, dehydration, and ketonuria, affecting 0.3-2% of pregnancies 2
• Evaluation should include assessment for signs of dehydration (orthostatic hypotension, decreased skin turgor, dry mucous membranes), malnutrition, and neurological deficits 1
• Laboratory tests should include electrolytes, liver function tests (elevated in 40-50% of HG cases), and urinalysis for ketonuria 1
• Abdominal ultrasonography helps rule out multiple/molar pregnancies and other causes like gallstones or portal vein thrombosis 1

First-Line Management

Non-pharmacological Interventions

• Dietary modifications including small, frequent, bland meals and avoiding food triggers 2
• Adequate hydration with oral fluids when possible 2, 3

Initial Pharmacological Management

• Vitamin B6 (pyridoxine) is recommended as first-line treatment for mild cases 1, 2
• Vitamin B1 (thiamine) supplementation is crucial to prevent Wernicke's encephalopathy:
  • Start with 100 mg daily for at least 7 days
  • Continue with maintenance dose of 50 mg daily until adequate oral intake is established 1, 3

Second-Line Management

• For patients who don't respond to first-line therapy, ACOG recommends a step-up approach 1
• First-line antiemetics according to European Association for the Study of the Liver guidelines:
  • Doxylamine with pyridoxine combination
  • Phenothiazines (monitor for extrapyramidal side effects) 1
• Second-line antiemetics:
  • Metoclopramide - similar efficacy to promethazine with fewer side effects and no increased risk of congenital defects 1
  • Ondansetron - use on case-by-case basis for persistent symptoms, especially after 10 weeks gestation due to potential risk of congenital heart defects in first trimester 1, 2

Management of Severe HG

• Hospitalization for IV hydration, electrolyte replacement, and nutritional support 1, 4
• Intravenous fluid resuscitation with particular attention to potassium and magnesium levels 2, 5
• Methylprednisolone as last resort for severe cases:
  • 16 mg IV every 8 hours for up to 3 days
  • Taper over 2 weeks to lowest effective dose
  • Limit duration to maximum 6 weeks
  • Use with caution before 10 weeks gestation due to potential risk of cleft palate 1
• Consider enteral or parenteral nutrition if weight loss and symptoms persist despite medical therapy 1, 5

Multidisciplinary Approach

• Treatment may require coordination between obstetricians, nutritionists, psychologists, and gastroenterologists 1, 2
• Mental health support is important to manage anxiety, depression, and emotional challenges associated with HG 1, 2

Monitoring and Follow-up

• Regular assessment of hydration status, electrolyte balance, and symptom control 2
• Monitor for complications including Wernicke's encephalopathy, thromboembolism, and electrolyte imbalances 3, 2
• Fetal growth monitoring, especially with insufficient maternal weight gain 2

Common Pitfalls and Caveats

• Failure to provide thiamine supplementation can lead to Wernicke's encephalopathy, a serious neurological complication 2, 3
• Ondansetron should be used cautiously before 10 weeks gestation due to potential cardiac risks 1
• Monitor for QT interval prolongation with ondansetron, especially in patients with electrolyte abnormalities 2
• Persistent liver chemistry abnormalities despite symptom resolution should prompt investigation for alternative diagnoses 2