What are the recommended treatments for managing 1st trimester nausea and vomiting?

Management of First Trimester Nausea and Vomiting

Start with dietary modifications and vitamin B6 for mild symptoms, escalate to doxylamine-pyridoxine combination for moderate symptoms, and use ondansetron or metoclopramide with IV hydration for severe symptoms or hyperemesis gravidarum. 1

Assess Severity First

Use the PUQE (Pregnancy-Unique Quantification of Emesis) score to guide treatment intensity: mild (≤6), moderate (7-12), or severe (≥13). 1 Hyperemesis gravidarum is defined by intractable vomiting, dehydration, weight loss >5% of prepregnancy weight, and electrolyte imbalances. 1

Early intervention is critical because once nausea and vomiting progresses, it becomes more difficult to control and may require hospitalization. 1, 2 Symptoms typically begin at 4-6 weeks, peak at 8-12 weeks, and resolve by week 20 in most women. 1

Mild Symptoms (PUQE ≤6)

Dietary and Lifestyle Modifications

• Eat small, frequent, bland meals (BRAT diet: bananas, rice, applesauce, toast). 1
• Choose high-protein, low-fat meals while avoiding spicy, fatty, acidic, and fried foods. 1
• Increase carbohydrate intake and decrease fat intake. 3
• Avoid bothersome food odors. 3

Non-Prescription Supplements

• Ginger 250 mg capsules four times daily is effective for mild symptoms. 1
• Vitamin B6 (pyridoxine) 10-25 mg every 8 hours can alleviate mild nausea. 1

Moderate Symptoms (PUQE 7-12)

The doxylamine-pyridoxine combination is FDA-approved and should be the first-line pharmacologic treatment for moderate symptoms. 1 This is the only medication specifically approved for nausea and vomiting of pregnancy.

Alternative H1-Receptor Antagonists

If doxylamine is unavailable or not tolerated:

• Promethazine 1
• Dimenhydrinate 1

These antihistamines target different pathways and are safe in pregnancy. 1

Severe Symptoms or Hyperemesis Gravidarum (PUQE ≥13)

Immediate Supportive Care

• IV hydration and electrolyte replacement are crucial first steps. 1
• Thiamine supplementation must be given to prevent Wernicke's encephalopathy, which can occur with prolonged vomiting. 1, 4

Pharmacologic Options

• Ondansetron (5-HT3 antagonist) is effective for severe symptoms. 1 Monitor for QTc prolongation with this medication. 5
• Metoclopramide (dopamine antagonist) promotes gastric emptying and reduces nausea. 1, 5
• IV glucocorticoids may be required in severe refractory cases, but avoid before 10 weeks gestation due to increased risk of oral clefts. 1

Critical Monitoring

• Liver enzyme abnormalities occur in approximately 50% of hyperemesis cases but rarely exceed 1,000 IU/mL and typically resolve with hydration. 1
• If liver chemistry abnormalities persist despite symptom resolution, investigate for another etiology. 1

Common Pitfalls to Avoid

Do not delay treatment due to unfounded concerns about medication safety—safe and effective treatments exist, and undertreating can lead to progression requiring hospitalization. 2, 6 Many women avoid seeking treatment because of medication safety concerns, but the FDA-approved doxylamine-pyridoxine combination has an established safety profile. 1, 2

Do not wait for severe dehydration or weight loss before initiating pharmacologic therapy—early intervention prevents progression to hyperemesis. 1, 2

Never skip thiamine supplementation in patients with hyperemesis gravidarum, as Wernicke's encephalopathy can develop and may be fatal. 1, 4

Refractory Cases

For women not responding to standard treatments:

• Consider a multidisciplinary approach involving maternal-fetal medicine specialists at a tertiary care center. 1
• Women with hyperemesis gravidarum are at higher risk for adverse pregnancy outcomes including low birth weight and premature delivery. 1
• In extreme cases of severe hyperemesis refractory to all treatments, corticosteroids may be considered after 10 weeks gestation. 1, 4

Algorithmic Approach Summary

1. Assess severity using PUQE score 1
2. Mild (≤6): Dietary modifications + ginger + vitamin B6 1
3. Moderate (7-12): Add doxylamine-pyridoxine combination 1
4. Severe (≥13): IV hydration + thiamine + ondansetron or metoclopramide 1
5. Refractory: Consider IV glucocorticoids (after 10 weeks) + specialist consultation 1