What are the treatment options for first trimester nausea and vomiting?

Treatment Options for First Trimester Nausea and Vomiting

For first trimester nausea and vomiting, a stepwise approach starting with diet and lifestyle modifications, followed by vitamin B6 (pyridoxine) with or without doxylamine, is recommended as first-line treatment, with additional medications like ondansetron, metoclopramide, and promethazine reserved for more severe cases. 1

Assessment of Severity

• Severity of nausea and vomiting during pregnancy (NVP) can be quantified using the Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score 1:
  • Mild: Score ≤6
  • Moderate: Score 7-12
  • Severe: Score ≥13
  • The score evaluates duration of nausea, frequency of vomiting, and frequency of retching over a 12-hour period 1

First-Line Non-Pharmacological Interventions

• Diet modifications 1:

  • Small, frequent, bland meals
  • BRAT diet (bananas, rice, applesauce, toast)
  • High-protein, low-fat meals
  • Avoid spicy, fatty, acidic, and fried foods

• Lifestyle modifications 1:

  • Identify and avoid specific triggers (certain foods with strong odors or activities)
  • Separate solid and liquid intake
  • Avoid empty stomach

First-Line Pharmacological Interventions

• Ginger 250 mg capsules four times daily 1

  • Recommended by American College of Obstetricians and Gynecologists (ACOG)
  • Safe and effective for mild symptoms

• Vitamin B6 (pyridoxine) 1, 2:

  • 10-25 mg every 8 hours (up to 40-60 mg/day)
  • Shown to significantly improve symptoms according to PUQE and Rhode's scores 2
  • FDA Pregnancy Category A (proven safety in pregnancy)

• Doxylamine (H1-receptor antagonist) 1, 3:

  • FDA-approved for NVP
  • Available in combination with pyridoxine (10 mg/10 mg or 20 mg/20 mg)
  • Recommended by ACOG for persistent NVP refractory to non-pharmacologic therapy
  • Safe and well-tolerated during pregnancy 3

Second-Line Pharmacological Interventions

• Other H1-receptor antagonists 1:

  • Promethazine
  • Dimenhydrinate
  • Considered safe first-line pharmacologic antiemetic therapies when needed

• Metoclopramide 1:

  • 5-10 mg orally every 6-8 hours
  • Meta-analysis of six cohort studies (33,000 first-trimester exposures) showed no significant increase in risk of major congenital defects (odds ratio 1.14,99% CI 0.93-1.38) 1

• Ondansetron 1, 4:

  • Can be used when other treatments fail
  • Small risk of cleft palate (0.03% absolute increase) and ventricular septal defects (0.3% absolute increase) 1
  • FDA-approved for chemotherapy-induced and post-operative nausea and vomiting 4

Third-Line Interventions for Severe Cases (Hyperemesis Gravidarum)

• Intravenous hydration and correction of electrolyte abnormalities 1

• Thiamine supplementation 1:

  • 300 mg daily with vitamin B complex if prolonged vomiting
  • Prevents Wernicke's encephalopathy

• Corticosteroids 1:

  • Methylprednisolone or prednisolone (preferred over dexamethasone or betamethasone)
  • Avoid before 10 weeks gestation due to increased risk of oral clefts
  • Consider for severe, refractory cases

Important Clinical Considerations

• Early intervention is crucial to prevent progression to hyperemesis gravidarum 1

• Hyperemesis gravidarum affects 0.3-2% of pregnancies and is characterized by 1:

  • Intractable vomiting
  • Dehydration
  • Weight loss >5% of prepregnancy weight
  • Electrolyte imbalances

• Most NVP begins at 4-6 weeks, peaks at 8-12 weeks, and subsides by week 20 1

• For patients with moderate to severe symptoms, a multidisciplinary approach involving obstetrics and gastroenterology may be beneficial 1

• Persistent liver chemistry abnormalities despite symptom resolution should prompt investigation for another etiology 1