What is the treatment for hyperemesis gravidarum?

Treatment of Hyperemesis Gravidarum

For hyperemesis gravidarum, begin with IV fluid resuscitation, thiamine supplementation, and doxylamine-pyridoxine combination as first-line antiemetic therapy, escalating to metoclopramide if symptoms persist, and reserving ondansetron and corticosteroids for refractory cases. 1

Initial Stabilization and Assessment

Immediate interventions upon presentation:

• Administer IV fluid resuscitation to correct dehydration, which often improves associated liver enzyme abnormalities 1
• Replace electrolytes with particular attention to potassium and magnesium levels 1
• Start thiamine 100 mg daily for minimum 7 days, then 50 mg daily maintenance until adequate oral intake is established to prevent Wernicke encephalopathy 2
• If vomiting persists or patient cannot tolerate oral intake, switch immediately to IV thiamine 200-300 mg daily 1

Essential laboratory evaluation:

• Check electrolyte panel, liver function tests (40-50% will have elevated AST/ALT, rarely >1,000 U/L), and urinalysis for ketonuria 2, 1
• Assess severity using the Pregnancy-Unique Quantification of Emesis (PUQE) score 1
• Perform abdominal ultrasonography to detect multiple or molar pregnancies and rule out hepatobiliary causes 2

Stepwise Pharmacologic Management

First-Line Therapy

Doxylamine-pyridoxine combination is the preferred initial antiemetic, safe throughout pregnancy and breastfeeding. 1 This represents the standard of care recommended by the American College of Obstetricians and Gynecologists. 1

Alternative first-line agents with similar safety profiles include: 1

• Promethazine (antihistamine)
• Cyclizine (antihistamine)
• Prochlorperazine (phenothiazine)
• Chlorpromazine (phenothiazine)

Critical caveat: Withdraw phenothiazines immediately if extrapyramidal symptoms develop. 1

Second-Line Therapy

Metoclopramide is the preferred second-line agent when first-line antihistamines fail. 1 In a randomized study comparing promethazine and metoclopramide in hospitalized patients, both had similar efficacy, but metoclopramide caused less drowsiness, dizziness, dystonia, and fewer treatment discontinuations. 2

Ondansetron should be reserved as second-line therapy due to concerns about congenital heart defects when used before 10 weeks gestation, though recent data suggest the risk is low. 1 The American College of Obstetricians and Gynecologists recommends using ondansetron on a case-by-case basis before 10 weeks of pregnancy. 2, 1

Important monitoring: Check for QT interval prolongation with ondansetron, especially in patients with electrolyte abnormalities. 1

Third-Line Therapy for Refractory Cases

Methylprednisolone should be reserved as last resort for severe hyperemesis gravidarum that fails other therapies. 1

Specific dosing protocol: 1

• 16 mg IV every 8 hours for up to 3 days
• Then taper over 2 weeks to lowest effective dose
• Maximum duration 6 weeks

Use with caution in first trimester due to slight increased risk of cleft palate when given before 10 weeks gestation. 1

Alternative refractory-case medications include olanzapine, gabapentin, and mirtazapine. 3

Non-Pharmacologic Interventions

Dietary modifications: 1

• Small, frequent, bland meals
• BRAT diet (bananas, rice, applesauce, toast)
• High-protein, low-fat meals
• Avoidance of specific food triggers and strong odors

Nutritional Support for Severe Cases

For patients with persistent weight loss despite maximizing antiemetics, consider enteral or parenteral nutrition. 3 Patients on total parenteral nutrition require minimum 2.5 mg/day thiamine in PN formulation, but for hyperemesis gravidarum specifically, provide 200-300 mg daily given increased metabolic demands. 1

Multidisciplinary Management

Severe cases require involvement of: 2, 1

• Obstetricians for pregnancy monitoring
• Gastroenterologists for refractory symptoms
• Nutritionists for dietary optimization
• Mental health professionals to manage anxiety, depression, and emotional challenges

Monitoring and Follow-Up

Regular assessments should include: 1

• Hydration status and electrolyte balance
• Symptom control using PUQE score
• Fetal growth monitoring, especially with insufficient maternal weight gain
• Monthly fetal growth scans from viability in severe cases

Key prognostic information: Symptoms resolve by week 16 in >50% of patients and by week 20 in 80%, though 10% experience symptoms throughout pregnancy. 2 Recurrence risk in subsequent pregnancies is 40-92%. 1

Important note: No significant efficacy difference exists among commonly used antiemetics (metoclopramide, ondansetron, promethazine) based on meta-analysis of 25 studies, so medication selection should be based on safety profile and gestational age. 2, 1