What are the treatment options for vomiting in pregnancy?

Treatment Options for Vomiting in Pregnancy

The initial management of nausea and vomiting in pregnancy should begin with dietary and lifestyle modifications, followed by vitamin B6 (pyridoxine) alone or in combination with doxylamine as first-line pharmacologic therapy for persistent symptoms. 1, 2

Assessment and Classification

Before initiating treatment, it's important to assess severity using the Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score:

• Mild (score ≤6)
• Moderate (score 7-12)
• Severe (score ≥13) 2

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
  • Stay hydrated with small, frequent sips of fluid
• Identify and avoid specific triggers (foods with strong odors or activities) 1

Step 2: First-line Pharmacological Treatment

• Vitamin B6 (pyridoxine): 10-25 mg every 8 hours 1, 2
• Doxylamine: 10-20 mg at bedtime or every 8 hours (can be combined with pyridoxine) 1
  • Available in 10 mg/10 mg and 20 mg/20 mg combinations with pyridoxine
  • FDA-approved and recommended by ACOG for persistent NVP 1

Step 3: Second-line Pharmacological Treatment

• H1-receptor antagonists: promethazine or dimenhydrinate 1
• Ondansetron: 4-8 mg every 8 hours for moderate to severe cases 1, 2, 3
  • Monitor for QT prolongation with ECG 2
• Metoclopramide: 10 mg every 6 hours with monitoring for extrapyramidal side effects 1, 2

Step 4: Management of Hyperemesis Gravidarum

For severe cases (hyperemesis gravidarum) with dehydration, weight loss >5% of pre-pregnancy weight, and electrolyte imbalances:

• Hospitalization for:
  • IV fluid and electrolyte replacement
  • IV thiamine supplementation (to prevent Wernicke's encephalopathy) 1
  • IV ondansetron or metoclopramide 2
  • Consider oral or IV corticosteroids for refractory cases 1

Special Considerations

Timing of Symptoms

• Nausea and vomiting typically begins at 4-6 weeks gestation
• Peaks at 8-12 weeks
• Usually subsides by week 20 1
• By week 16, symptoms resolve in >50% of women with hyperemesis gravidarum
• By week 20,80% improve, but 10% may have persistent symptoms throughout pregnancy 1

Safety Profile of Medications

• Pyridoxine and doxylamine combination is safe and well-tolerated in pregnancy 1, 2
• Ondansetron has favorable pregnancy safety profile, though recent data on first trimester use is mixed 1, 2, 3
• Corticosteroids should be reserved for refractory cases due to potential risks with prolonged use 2

Prevention of Progression

• Early intervention and treatment of NVP may help prevent progression to hyperemesis gravidarum, which affects 0.3-2% of pregnant women 1, 2
• Recurrence of hyperemesis gravidarum is high in subsequent pregnancies 1

Monitoring

• For persistent liver chemistry abnormalities despite symptom resolution, investigate for other etiologies 1
• Monitor for signs of dehydration, electrolyte imbalances, and weight loss in moderate to severe cases 1

By following this stepwise approach, most cases of nausea and vomiting in pregnancy can be effectively managed while minimizing risks to both mother and fetus.