What is the best course of treatment for a pregnant female experiencing severe vomiting and nausea?

Management of Severe Nausea and Vomiting in Pregnancy (Hyperemesis Gravidarum)

For pregnant women with severe vomiting and nausea, initiate immediate treatment with IV hydration, thiamine supplementation (100-300 mg IV daily), and the doxylamine-pyridoxine combination as first-line antiemetic therapy, escalating to metoclopramide or ondansetron if symptoms persist, and reserving corticosteroids only for refractory cases after 10 weeks gestation. 1, 2

Initial Assessment and Stabilization

Immediate priorities:

• Check electrolytes (particularly potassium and magnesium), liver function tests (elevated in 40-50% of cases), urinalysis for ketonuria, and thyroid function tests 1, 2
• Assess severity using the PUQE score: mild (≤6), moderate (7-12), severe (≥13) 1, 2
• Look for signs of dehydration (orthostatic hypotension, decreased skin turgor, dry mucous membranes), weight loss ≥5% of pre-pregnancy weight, and neurologic signs suggesting Wernicke's encephalopathy (confusion, ataxia, eye movement abnormalities) 1, 2

Critical first step: Start IV thiamine 100-300 mg daily BEFORE any dextrose-containing fluids to prevent Wernicke's encephalopathy, as pregnancy depletes thiamine stores within 7-8 weeks of persistent vomiting 1, 3

Stepwise Pharmacologic Treatment Algorithm

First-Line Therapy (Start Immediately)

• Doxylamine 10-20 mg + Pyridoxine (Vitamin B6) 10-20 mg every 8 hours - this is the only FDA-approved combination and should be the initial pharmacologic choice 1, 2, 3
• Alternative first-line agents if doxylamine unavailable: promethazine, dimenhydrinate, or other H1-receptor antagonists 1, 3
• Continue thiamine 100 mg IV daily for minimum 7 days, then 50 mg daily maintenance until adequate oral intake established 1, 3

Second-Line Therapy (If First-Line Fails After 24-48 Hours)

• Metoclopramide 5-10 mg IV every 6-8 hours - preferred second-line agent with less drowsiness and dystonia than promethazine 1, 3
• Ondansetron 0.15 mg/kg (max 16 mg) IV over 15 minutes - use with caution before 10 weeks gestation due to small absolute risk increase in cleft palate (0.03%) and ventricular septal defects (0.3%) 1, 3
• The American College of Obstetricians and Gynecologists recommends ondansetron on a case-by-case basis before 10 weeks 1, 3

Important caveat: Withdraw metoclopramide immediately if extrapyramidal symptoms develop 1

Third-Line Therapy (Severe Refractory Cases Only)

• Methylprednisolone 16 mg IV every 8 hours for up to 3 days, then taper over 2 weeks to lowest effective dose, maximum 6 weeks duration 1, 3
• Avoid corticosteroids before 10 weeks gestation due to slight increased risk of cleft palate 1, 3
• At 20 weeks gestation, corticosteroid use is safer and reduces rehospitalization rates 3

Supportive Care Requirements

IV fluid resuscitation:

• Normal saline (0.9% NaCl) plus potassium chloride guided by daily electrolyte monitoring 3
• Replace magnesium aggressively as hypomagnesemia is common 1

Nutritional support:

• Start with small, frequent, bland meals (BRAT diet: bananas, rice, applesauce, toast) when tolerating oral intake 1, 2
• High-protein, low-fat meals; avoid spicy, fatty, acidic, and fried foods 1, 2
• Consider nasojejunal feeding (preferred over nasogastric) if unable to maintain 1000 kcal/day for several days despite maximal medical therapy 1
• Enteral feeding should NOT be used for food aversions alone, only for true nutritional failure 1

Common Pitfalls to Avoid

Don't skip the stepwise approach - jumping directly to ondansetron or corticosteroids without trying doxylamine-pyridoxine first violates evidence-based guidelines 1, 3

Don't use PRN dosing in severe cases - switch to scheduled around-the-clock antiemetic administration for better symptom control 1

Don't forget thiamine BEFORE dextrose - this prevents Wernicke's encephalopathy, which can be fatal 1, 3

Don't delay treatment - early aggressive intervention prevents progression from mild nausea to hyperemesis gravidarum 1, 2, 4

Monitoring and Follow-Up

• Reassess PUQE score every 1-2 weeks during acute phase 1
• Monitor weight trajectory - stabilization or gain (not continued loss) indicates clinical improvement 1
• Check electrolytes daily while hospitalized 1, 3
• If liver enzymes remain elevated despite symptom resolution, investigate alternative causes 1, 2
• Most cases resolve by week 16-20 (80%), though 10% experience symptoms throughout pregnancy 1, 2

When to Hospitalize

Admit for IV therapy if:

• Persistent vomiting despite oral antiemetics 3
• Signs of dehydration or electrolyte abnormalities 3
• Weight loss >5% of pre-pregnancy weight 1, 3
• Inability to tolerate oral intake 3
• Ketonuria persists 1

Multidisciplinary Involvement

For severe refractory cases, coordinate care with maternal-fetal medicine, gastroenterology, nutrition services, and mental health professionals, preferably at tertiary care centers 1, 2, 3

Mental health support is important as anxiety and depression are common with severe hyperemesis 1

Prognosis

Untreated hyperemesis is associated with low birth weight, small for gestational age infants, and premature delivery 1, 2

Recurrence risk in subsequent pregnancies is 40-92% - consider pre-emptive antiemetic therapy starting before conception or immediately at symptom onset in future pregnancies 1, 4