Management of Vomiting in Pregnancy
The stepwise treatment of nausea and vomiting in pregnancy should begin with dietary and lifestyle modifications, followed by vitamin B6 and doxylamine, with ondansetron, metoclopramide, promethazine, and intravenous glucocorticoids reserved for moderate to severe cases. 1
Assessment and Classification
First, assess the severity of nausea and vomiting using the Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score:
| Variable | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|
| Hours felt nauseated (past 12h) | Not at all | 1 | 2-3 | 4-6 | >6 |
| Number of vomiting episodes | None | 1-2 | 3-4 | 5-6 | ≥7 |
| Number of retching/dry heaves | None | 1-2 | 3-4 | 5-6 | ≥7 |
- Score ≤6: Mild
- Score 7-12: Moderate
- Score ≥13: Severe
Treatment Algorithm
Step 1: Dietary and Lifestyle Modifications (All Patients)
- Eat small, frequent, bland meals (BRAT diet: bananas, rice, applesauce, toast)
- Focus on high-protein, low-fat meals
- Identify and avoid specific triggers (foods with strong odors)
- Avoid spicy, fatty, acidic, and fried foods
- Stay hydrated with small, frequent sips of fluid
Step 2: Non-Pharmacological Approaches (Mild Cases)
- Ginger 250 mg capsules four times daily
- Consider acupressure at P6 point (wrist)
Step 3: First-Line Pharmacological Treatment (Mild to Moderate Cases)
- Vitamin B6 (pyridoxine) 10-25 mg every 8 hours
- Add doxylamine 10-20 mg at bedtime or every 8 hours
- Combination products containing both are available and FDA-approved
Step 4: Second-Line Pharmacological Treatment (Moderate Cases)
- Antihistamines (if doxylamine unsuccessful): promethazine or dimenhydrinate
- Metoclopramide 10 mg every 6 hours (monitor for extrapyramidal side effects)
- Ondansetron 4-8 mg every 8 hours (consider ECG monitoring for QT prolongation)
Step 5: Severe Cases/Hyperemesis Gravidarum
- Hospitalization for IV fluid and electrolyte replacement
- IV thiamine supplementation (to prevent Wernicke's encephalopathy)
- IV ondansetron or metoclopramide
- Consider IV corticosteroids for refractory cases
- Monitor for electrolyte imbalances and ketosis
Important Considerations
Timing of Treatment
Early intervention is critical as it may prevent progression to hyperemesis gravidarum, which affects 0.3-2% of pregnant women 1. Nausea and vomiting typically begins at 4-6 weeks, peaks at 8-12 weeks, and resolves by week 20 in most women.
Safety Concerns
Many women avoid treatment due to concerns about medication safety 2. However, untreated severe nausea and vomiting can lead to:
- Dehydration
- Weight loss >5% of pre-pregnancy weight
- Electrolyte imbalances
- Nutritional deficiencies
- Increased risk of low birth weight and preterm delivery
Hyperemesis Gravidarum Warning Signs
- Weight loss >5% of pre-pregnancy weight
- Dehydration
- Electrolyte abnormalities
- Ketonuria
- Inability to keep down fluids for >24 hours
Medication Safety
- Pyridoxine and doxylamine have been extensively studied and are considered safe in pregnancy 1
- Ondansetron efficacy is well-established, though recent data on safety in first trimester is mixed
- Corticosteroids should be reserved for refractory cases due to potential risks with prolonged use
Common Pitfalls to Avoid
- Delayed treatment - Early intervention prevents progression to more severe disease
- Dismissing symptoms as "normal morning sickness" when they are severe
- Failing to rule out other causes of vomiting (e.g., gastroenteritis, pancreatitis, hepatitis)
- Not providing adequate hydration - IV fluids may be necessary even before hospitalization
- Overlooking nutritional deficiencies - Thiamine supplementation is essential in prolonged vomiting
Remember that nausea and vomiting of pregnancy affects 30-90% of pregnant women 1 and can significantly impact quality of life. Taking symptoms seriously and providing prompt, appropriate treatment is essential for maternal and fetal wellbeing.