What is the treatment for hyperemesis gravidarum?

Treatment of Hyperemesis Gravidarum

First-line treatment for hyperemesis gravidarum should include vitamin B6 (pyridoxine), doxylamine, and phenothiazines such as promethazine, prochlorperazine, and cyclizine, with appropriate hydration and electrolyte management. 1, 2

Definition and Clinical Presentation

• Hyperemesis gravidarum (HG) is an intractable form of nausea and vomiting in pregnancy characterized by persistent vomiting, weight loss ≥5% of pre-pregnancy weight, dehydration, and ketonuria 2
• HG affects 0.3-2% of pregnancies and typically starts before week 22 of gestation 1
• Symptoms resolve by week 16 in >50% of patients and by week 20 in 80%, though 10% may experience symptoms throughout pregnancy 2

Diagnostic Evaluation

• Comprehensive history including previous pregnancies (higher risk in subsequent pregnancies) and pre-existing conditions 1, 2
• Physical examination focusing on signs of dehydration (orthostatic hypotension, decreased skin turgor, dry mucous membranes) 1
• Laboratory evaluation for dehydration, electrolyte imbalances, and nutritional deficiencies 1
• Liver enzymes may be elevated in 40-50% of HG patients 1
• Abdominal ultrasonography to detect multiple or molar pregnancies and rule out hepatobiliary causes 1, 2

Treatment Algorithm

Non-pharmacological Interventions

• Diet modifications including small, frequent, bland meals and avoidance of food triggers 2
• High-protein, low-fat meals may be beneficial 2

First-Line Pharmacological Treatment

• Vitamin B6 (pyridoxine) is recommended as first-line treatment for mild cases 1, 2
• Doxylamine/pyridoxine combination 1, 2
• Phenothiazines (promethazine, prochlorperazine, chlorpromazine) 1, 2
• Cyclizine 1

Second-Line Pharmacological Treatment

• Metoclopramide - effective with fewer side effects than promethazine 1
• Domperidone 1
• Ondansetron - primarily for severe cases requiring hospitalization 1
  • Note: ACOG recommends using ondansetron on a case-by-case basis in patients with persistent symptoms before 10 weeks of pregnancy due to some studies reporting congenital heart defects 1

Third-Line Treatment for Refractory Cases

• Corticosteroids are recommended for intractable cases 1, 2, 3
  • A study showed significant reduction in vomiting episodes with hydrocortisone compared to metoclopramide 3
  • However, another study found no difference in rehospitalization rates between corticosteroids and placebo 4
• Alternative medications for refractory cases include:
  • Mirtazapine - shown to be effective in case reports of severe HG not responding to conventional treatments 5, 6
  • Olanzapine and gabapentin may be considered in resistant cases 6

Nutritional Support

• Thiamine (vitamin B1) supplementation (100 mg daily for at least 7 days, followed by 50 mg daily) is essential to prevent refeeding syndrome and Wernicke encephalopathy 1
• For prolonged cases with ongoing weight loss, enteral or parenteral nutrition may be necessary 6

Management of Hospitalized Patients

• Intravenous fluid resuscitation and electrolyte replacement 2, 6
• Intravenous antiemetics when oral intake is not possible 6
• Regular monitoring of hydration status, electrolyte balance, and symptom control 2

Complications and Prognosis

• Untreated HG is associated with low birth weight, small for gestational age infants, and premature delivery 1, 2
• Early intervention is crucial to prevent progression from mild nausea and vomiting to hyperemesis gravidarum 2
• Severe cases may require a multidisciplinary approach involving obstetricians, gastroenterologists, nutritionists, and mental health professionals 1, 2, 6