What is the treatment for nausea and vomiting in pregnancy?

Treatment of Nausea and Vomiting in Pregnancy

The treatment of nausea and vomiting in pregnancy should follow a stepwise approach starting with dietary and lifestyle modifications, followed by vitamin B6 and doxylamine as first-line pharmacologic therapy, with additional medications reserved for moderate to severe cases. 1

Assessment and Classification

First, assess severity using the Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score:

• Mild: Score ≤6
• Moderate: Score 7-12
• Severe: Score ≥13

The PUQE score evaluates:

1. Duration of nausea (hours/day)
2. Number of vomiting episodes
3. Number of retching episodes

Treatment Algorithm

Step 1: Non-pharmacologic Approaches (All Patients)

• Dietary modifications:

  • Small, frequent meals (5-6 per day)
  • Low-fat, bland foods (BRAT diet: bananas, rice, applesauce, toast)
  • High-protein, low-fat meals
  • Avoid spicy, fatty, acidic, and fried foods
  • Separate solids and liquids by 20-30 minutes
  • Cold foods may be better tolerated (less aroma)

• Lifestyle modifications:

  • Identify and avoid specific triggers (foods with strong odors)
  • Rest in a quiet environment
  • Avoid sudden movements

Step 2: First-line Pharmacologic Therapy (Mild to Moderate Symptoms)

• Vitamin B6 (pyridoxine): 10-25 mg every 8 hours 1
• Doxylamine: 10-20 mg combined with pyridoxine 10-20 mg 1
  • FDA-approved combination available (Diclegis/Bonjesta)
  • Can be taken separately if combination not available

Step 3: Second-line Therapy (Moderate Symptoms)

• H1-receptor antagonists: 1
  • Promethazine 12.5-25 mg orally or rectally every 4-6 hours
  • Dimenhydrinate 50-100 mg orally or rectally every 4-6 hours

Step 4: Third-line Therapy (Moderate to Severe Symptoms)

• Dopamine antagonists: 1
  • Metoclopramide 5-10 mg orally or IV every 6-8 hours
• Serotonin antagonists:
  • Ondansetron 4-8 mg orally or IV every 8 hours

Step 5: Severe Cases/Hyperemesis Gravidarum

• Hospitalization for:
  • IV hydration
  • Electrolyte correction
  • Nutritional support
• Intravenous glucocorticoids for refractory cases 1
  • Methylprednisolone 16 mg IV every 8 hours, then taper

Special Considerations

Hyperemesis Gravidarum

Defined by:

• Intractable vomiting
• Weight loss >5% of pre-pregnancy weight
• Dehydration
• Electrolyte abnormalities

Requires more aggressive management including:

• IV fluid replacement
• Correction of electrolyte imbalances
• Possible total parenteral nutrition in extreme cases
• Early intervention is crucial to prevent progression 1, 2

Timing of Treatment

• NVP typically begins at 4-6 weeks gestation
• Peaks at 8-12 weeks
• Usually resolves by week 20
• Early treatment may prevent progression to hyperemesis gravidarum 1

Safety Considerations

• Doxylamine and pyridoxine combination has FDA pregnancy category A rating 3
• Most antiemetics have been shown to be safe in pregnancy
• The risks of untreated severe NVP (dehydration, weight loss, electrolyte imbalances) often outweigh the potential risks of medication 4

Monitoring

• Regular weight checks
• Assess hydration status
• Monitor for ketones in urine
• Evaluate electrolytes in severe cases
• Reassess PUQE score to determine treatment efficacy

Pitfalls to Avoid

• Delaying treatment due to unfounded medication safety concerns
• Failing to recognize hyperemesis gravidarum requiring hospitalization
• Not ruling out other causes of nausea and vomiting (e.g., gastroenteritis, thyroid disease, hepatitis)
• Underestimating the impact of NVP on maternal quality of life and potential fetal outcomes

Early, appropriate treatment of nausea and vomiting in pregnancy is essential for improving maternal quality of life and preventing progression to more severe forms that could impact maternal and fetal health.