What are the treatment options for nausea and vomiting in pregnancy?

Management of Nausea and Vomiting in Pregnancy

Early treatment of nausea and vomiting in pregnancy should follow a stepwise approach beginning with vitamin B6 and doxylamine, followed by metoclopramide or ondansetron for moderate to severe cases, with intravenous hydration and corticosteroids reserved for hyperemesis gravidarum. 1, 2

Understanding Nausea and Vomiting in Pregnancy (NVP)

• Affects 30-90% of pregnant women 2
• Typically begins at 4-6 weeks gestation, peaks at 8-12 weeks, and usually subsides by week 20 1, 2
• Can progress to hyperemesis gravidarum (HG) in 0.3-2% of pregnancies, characterized by:
  • Intractable vomiting
  • Dehydration
  • Weight loss >5% of pre-pregnancy weight
  • Electrolyte imbalances 2

Assessment of Severity

The Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score can help assess severity 1, 2:

Variable	1	2	3	4	5
In the past 12h: How long (h) have you felt nauseated?	Not at all	1	2-3	4-6	>6
How many times have you vomited?	None	1-2	3-4	5-6	≥7
How many times have you had dry heaves?	None	1-2	3-4	5-6	≥7

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

Treatment Algorithm

Step 1: Non-pharmacological Approaches

• Dietary modifications:
  • Small, frequent, bland meals
  • High-protein, low-fat meals
  • Avoid spicy, fatty, acidic, and fried foods 2
• Lifestyle adjustments:
  • Identify and avoid specific triggers (strong odors, activities)
  • Stay hydrated with small, frequent sips of fluid 2
• Ginger 250 mg capsules four times daily 2

Step 2: First-line Pharmacological Options

• Vitamin B6 (pyridoxine) 10-25 mg every 8 hours, alone or with doxylamine 1, 2
• Doxylamine 10-20 mg at bedtime or every 8 hours 2

Step 3: Second-line Options for Moderate to Severe Cases

• Metoclopramide 5-10 mg orally every 6-8 hours
  • Safe in pregnancy with no significant increase in risk of major congenital defects 2
  • Monitor for extrapyramidal side effects 1, 2
• Ondansetron 4-8 mg every 8 hours
  • Note: Small absolute risk increase for orofacial clefts (0.03%) and ventricular septal defects (0.3%) 2, 3
  • Should be used with caution in early first trimester 2
• Promethazine or other H1-receptor antagonists 1, 2

Step 4: Management of Hyperemesis Gravidarum

• IV fluid and electrolyte replacement
• IV thiamine supplementation (100 mg daily for minimum 7 days, followed by 50 mg daily until adequate oral intake) 2
• IV antiemetics (ondansetron or metoclopramide) 2
• Corticosteroids for refractory cases:
  • Methylprednisolone or prednisolone
  • Avoid before 10 weeks gestation due to increased risk of oral clefts 2
  • Betamethasone and dexamethasone are contraindicated 2

Important Considerations

• Early intervention is critical to prevent progression to hyperemesis gravidarum 2
• Reassess symptoms after initial treatment using the PUQE score 2
• For persistent symptoms, consider:
  • Continuing for another short course
  • Adding another antiemetic
  • Switching to a different antiemetic class 2
• Hospitalization criteria:
  • Dehydration
  • Weight loss >5% of pre-pregnancy weight
  • Electrolyte imbalances 1, 2

Common Pitfalls to Avoid

• Delaying treatment due to unfounded concerns about medication safety 2
• Failing to recognize hyperemesis gravidarum requiring hospitalization 2
• Using ondansetron in early first trimester without considering potential risks 2, 3
• Using NK-1 antagonists like aprepitant which have limited human data in pregnancy 2
• Using second-generation antipsychotics like olanzapine which have been linked to increased risk for ventricular and septal defects 2

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