Management of Hyperemesis Gravidarum
The management of hyperemesis gravidarum should focus on rehydration, correction of electrolyte abnormalities, thiamine supplementation, and appropriate anti-emetic therapy, with escalation of care based on severity of symptoms. 1
Definition and Diagnosis
Hyperemesis gravidarum (HG) is characterized by:
- Intractable nausea and vomiting
- Weight loss >5% of pre-pregnancy weight
- Dehydration
- Electrolyte imbalances
- Ketonuria
HG affects 0.3-2% of pregnant individuals, typically starting before week 22 of gestation, with symptoms resolving in >50% by week 16 and 80% by week 20. However, 10% of cases persist throughout pregnancy and occasionally into the postpartum period. 1
Initial Assessment
Evaluation should include:
- Comprehensive history (including previous pregnancies with HG)
- Physical examination for signs of dehydration:
- Orthostatic hypotension
- Decreased skin turgor
- Dry mucous membranes
- Weight loss and muscle wasting
- Laboratory evaluation:
- Electrolytes (hyponatremia, hypokalaemia common)
- Liver function tests (elevated in 40-50% of HG cases)
- Urinalysis for ketones
- Thyroid function tests (may show biochemical hyperthyroidism)
- Abdominal ultrasound to detect multiple/molar pregnancies and rule out other causes 1
Management Algorithm
Step 1: Dietary and Lifestyle Modifications
- Small, frequent, bland meals
- High-protein, low-fat meals
- BRAT diet (bananas, rice, applesauce, toast)
- Avoid spicy, fatty, acidic, and fried foods
- Identify and avoid specific triggers (foods with strong odors)
- Stay hydrated with small, frequent sips of fluid 1, 2
Step 2: First-Line Pharmacologic Therapy
For persistent symptoms despite lifestyle modifications:
- Vitamin B6 (pyridoxine): 10-25 mg every 8 hours
- Doxylamine: 10-20 mg at bedtime or every 8 hours
- Available in combination with pyridoxine (10 mg/10 mg or 20 mg/20 mg)
- Ginger: 250 mg capsule 4 times daily 1, 2
Step 3: Second-Line Pharmacologic Therapy
For moderate to severe symptoms:
- H1-receptor antagonists:
- Doxylamine (FDA-approved)
- Promethazine
- Dimenhydrinate
- Metoclopramide: 10 mg every 6 hours (monitor for extrapyramidal side effects)
- Ondansetron: 4-8 mg every 8 hours (caution before 10 weeks; monitor ECG for QT prolongation) 1, 2
Step 4: Hospitalization
Indications for hospitalization:
- Dehydration
- Weight loss >5% of pre-pregnancy weight
- Electrolyte imbalances
- Failed outpatient management
Hospital management includes:
- IV fluid and electrolyte replacement
- IV thiamine supplementation (100 mg daily for minimum 7 days) to prevent Wernicke's encephalopathy
- IV anti-emetics (ondansetron or metoclopramide)
- IV corticosteroids may be considered for refractory cases, though evidence is conflicting 1, 2, 3
Monitoring and Follow-up
- Regular assessment of weight, hydration status, and electrolytes
- Monitor liver function tests if initially abnormal
- Persistent liver chemistry abnormalities despite symptom resolution should prompt investigation for another etiology
- Neurologic evaluation for neuropathy or vitamin deficiency if indicated 1
Complications and Prognosis
Without adequate treatment, HG can lead to:
Recurrence risk is high in subsequent pregnancies
No association with chronic liver disease 1
Common Pitfalls to Avoid
- Delaying treatment due to unfounded concerns about medication safety
- Failing to provide thiamine supplementation
- Inadequate fluid and electrolyte replacement
- Not recognizing severe cases requiring hospitalization
- Overlooking other causes of severe nausea and vomiting (e.g., thyrotoxicosis, urinary tract infection) 2, 5
Early intervention and treatment of nausea and vomiting in pregnancy may help prevent progression to hyperemesis gravidarum, improving maternal and fetal outcomes. 1