What is the management approach for vomiting in pregnancy?

Management of Vomiting in Pregnancy

For vomiting in pregnancy, start with dietary modifications (small frequent bland meals, BRAT diet), followed by ginger (250mg four times daily) and vitamin B6 (10-25mg every 8 hours), then add antihistamines like doxylamine if needed, with escalation to metoclopramide or ondansetron for refractory cases. 1, 2

Initial Assessment and Approach

• Nausea and vomiting in pregnancy (NVP) affects 30-90% of pregnant women, typically beginning at 4-6 weeks, peaking at 8-12 weeks, and resolving by week 20 2, 3
• Assess severity using the Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score:
  • Mild (score ≤6)
  • Moderate (score 7-12)
  • Severe (score ≥13) 2
• Distinguish from hyperemesis gravidarum (HG), which affects 0.3-2% of pregnant women and involves:
  • Intractable vomiting
  • Dehydration
  • Weight loss >5% of pre-pregnancy weight
  • Electrolyte imbalances 1

Treatment Algorithm

Step 1: Non-pharmacological Interventions

• Dietary modifications:
  • Small, frequent, bland meals
  • BRAT diet (bananas, rice, applesauce, toast)
  • High-protein, low-fat meals
  • Avoid spicy, fatty, acidic, and fried foods 1, 2
• Lifestyle adjustments:
  • Identify and avoid specific triggers (strong odors, activities)
  • Stay hydrated with small, frequent sips of fluid 1, 2

Step 2: First-line Pharmacological Treatment

• Vitamin B6 (pyridoxine): 10-25 mg every 8 hours 1, 2
• Ginger: 250 mg capsule 4 times daily 1
• Combination therapy: Doxylamine and pyridoxine (available in 10mg/10mg and 20mg/20mg combinations) 1, 2

Step 3: Second-line Pharmacological Treatment

• H1-receptor antagonists:
  • Doxylamine (10-20 mg at bedtime or every 8 hours)
  • Promethazine
  • Dimenhydrinate 1

Step 4: Refractory Cases

• Metoclopramide: 10 mg every 6 hours (monitor for extrapyramidal side effects) 1, 2
• Ondansetron: 4-8 mg every 8 hours for moderate to severe cases (use with caution before 10 weeks; monitor ECG for QT prolongation) 2
• Prochlorperazine: Use with caution in pregnancy; safety not established but may be considered in severe cases when benefits outweigh risks 4

Management of Hyperemesis Gravidarum

Indications for Hospitalization

• Dehydration
• Weight loss >5% of pre-pregnancy weight
• Electrolyte imbalances 1, 2

Hospital Management

1. IV fluid and electrolyte replacement
2. IV thiamine supplementation (100 mg daily for minimum 7 days, followed by 50 mg daily until adequate oral intake) 1, 2
3. IV antiemetics (ondansetron or metoclopramide)
4. Consider IV corticosteroids for refractory cases 2

Special Considerations

Post-Bariatric Surgery Patients

• For patients with adjustable gastric banding who develop hyperemesis:
  • Consider band deflation to prevent band slippage and nutrient deficiencies
  • Provide thiamine 300 mg daily with vitamin B compound if vomiting persists
  • Prolonged vomiting may require IV thiamine and vitamin B complex supplementation 1

Common Pitfalls to Avoid

• Delaying treatment due to unfounded concerns about medication safety
• Using ondansetron in early first trimester without proper consideration
• Failing to recognize hyperemesis gravidarum requiring hospitalization
• Not providing adequate thiamine supplementation, which can lead to Wernicke encephalopathy 2

Early intervention is critical to prevent progression to hyperemesis gravidarum and reduce maternal and fetal complications. The stepwise approach allows for tailoring treatment based on symptom severity while maintaining safety during pregnancy.