What is the management of hyperemesis gravidarum?

Management of Hyperemesis Gravidarum

Start with IV fluid resuscitation, thiamine 200-300 mg IV daily, electrolyte replacement, and first-line antiemetics (doxylamine-pyridoxine), escalating to metoclopramide or ondansetron for refractory cases, and reserve corticosteroids only for severe cases failing all other therapies. 1

Initial Assessment and Stabilization

Diagnostic Workup

• Assess severity using the PUQE (Pregnancy-Unique Quantification of Emesis) score, which evaluates duration of nausea, frequency of vomiting, and retching over 12 hours 1, 2
• Confirm diagnosis by documenting weight loss ≥5% of pre-pregnancy weight, dehydration signs, and ketonuria 1, 2
• Order electrolyte panel, liver function tests (50% will have abnormal AST/ALT, rarely >1,000 U/L), and urinalysis for ketones 1
• Obtain abdominal ultrasound to detect multiple or molar pregnancies and assess fetal growth 1
• Check thyroid function as hyperemesis can cause biochemical hyperthyroidism with undetectable TSH 1, 2

Immediate Stabilization

• Administer IV fluid resuscitation immediately to correct dehydration, which often improves liver chemistry abnormalities 1, 2
• Give thiamine 200-300 mg IV daily for at least 3-5 days to prevent Wernicke's encephalopathy, as thiamine stores can be depleted within 7-8 weeks of persistent vomiting 1
• Replace electrolytes with particular attention to potassium and magnesium levels 1, 2

Stepwise Pharmacologic Management

First-Line Antiemetics

• Prescribe doxylamine-pyridoxine combination as the preferred initial antiemetic, safe throughout pregnancy and breastfeeding 1
• Alternative first-line agents include antihistamines (promethazine, cyclizine) or phenothiazines (prochlorperazine, chlorpromazine), all with similar safety profiles 1
• Vitamin B6 (pyridoxine) alone may be used for mild cases 1

Second-Line Therapy (When First-Line Fails)

• Use metoclopramide as the preferred second-line agent, which causes less drowsiness, dizziness, and dystonia compared to promethazine 1
• Reserve ondansetron for second-line use due to concerns about congenital heart defects when used before 10 weeks gestation, though recent data suggest low risk 1
• Use ondansetron on a case-by-case basis before 10 weeks of pregnancy 1
• Both metoclopramide and ondansetron are compatible throughout pregnancy and breastfeeding 1
• Monitor QT interval with ondansetron, especially in patients with electrolyte abnormalities 1

Third-Line Therapy (Severe Refractory Cases)

• Reserve methylprednisolone only for severe hyperemesis failing all other therapies: 16 mg IV every 8 hours for up to 3 days, then taper over 2 weeks to lowest effective dose, maximum duration 6 weeks 1
• Use corticosteroids with caution in first trimester due to slight increased risk of cleft palate when given before 10 weeks 1

Alternative Pharmacotherapeutics for Refractory Cases

• Consider mirtazapine, olanzapine, or gabapentin when typical antiemetics fail 1, 3

Non-Pharmacological Interventions

• Recommend small, frequent, bland meals using the BRAT diet (bananas, rice, applesauce, toast) 1
• Advise high-protein, low-fat meals and avoidance of specific food triggers and strong odors 1
• Ginger supplementation may provide benefit 1, 4

Thiamine Dosing Algorithm by Severity

Mild to Moderate Cases (Tolerating Oral Intake)

• Thiamine 300 mg orally daily plus vitamin B compound strong: 2 tablets three times daily until vomiting resolves 1

Severe Cases or Inability to Tolerate Oral Intake

• Switch immediately to thiamine 200-300 mg IV daily for at least 3-5 days, then transition to oral maintenance (50-100 mg daily) once vomiting controlled 1

Suspected or Confirmed Wernicke's Encephalopathy

• Administer thiamine 500 mg IV three times daily (1,500 mg total daily dose) 1

Patients on Total Parenteral Nutrition

• Provide 200-300 mg thiamine daily in PN formulation given increased metabolic demands 1

Monitoring and Follow-Up

• Regularly assess hydration status and electrolyte balance 1, 2
• Evaluate symptom control using PUQE score at each visit 1, 2
• Check thiamine status (RBC or whole blood thiamine diphosphate) every trimester, particularly in patients with inadequate weight gain 1
• Monitor fetal growth, especially with insufficient maternal weight gain; consider monthly fetal growth scans from viability in severe cases 1, 2
• For monochorionic-diamniotic twins, perform routine ultrasound surveillance for twin-twin transfusion syndrome beginning at 16 weeks and continuing every 2 weeks until delivery 2

Important Caveats and Pitfalls

• Withdraw phenothiazines or metoclopramide immediately if extrapyramidal symptoms develop 1
• Persistent liver chemistry abnormalities despite symptom resolution should prompt investigation for another etiology 1
• Early intervention is crucial to prevent progression from mild nausea and vomiting to hyperemesis gravidarum 1
• No significant efficacy difference exists among commonly used antiemetics (metoclopramide, ondansetron, promethazine) based on meta-analysis 1

Severe Cases Requiring Advanced Support

• Hospitalize patients with persistent weight loss for IV hydration 1
• Consider enteral or parenteral nutrition when oral intake is not tolerated for prolonged periods with ongoing weight loss 1, 3
• Coordinate care with multidisciplinary team including obstetricians, gastroenterologists, nutritionists, and mental health professionals, preferably at tertiary care centers experienced in high-risk pregnancies 1

Patient Counseling

• Educate patients about high recurrence risk (40-92%) in subsequent pregnancies 1
• Inform patients that symptoms typically resolve by week 16-20 in 80% of cases, though 10% may experience symptoms throughout pregnancy 1
• Explain that untreated hyperemesis is associated with low birth weight, small for gestational age infants, and premature delivery 1