What are the differentials and management options for a pregnant patient experiencing vomiting after meals at 30 weeks of gestation?

Differential Diagnosis for Vomiting After Meals at 30 Weeks Gestation

At 30 weeks gestation, vomiting after meals is atypical for standard nausea and vomiting of pregnancy (which typically resolves by week 20), and you must systematically evaluate for both pregnancy-specific and general gastrointestinal causes before defaulting to a diagnosis of persistent NVP. 1, 2

Key Timing Consideration

• Nausea and vomiting of pregnancy typically begins at 4-6 weeks, peaks at 8-12 weeks, and subsides by week 20 in most women 3, 2
• Vomiting presenting or persisting at 30 weeks warrants investigation for alternative etiologies beyond typical NVP 2

Differential Diagnoses to Consider

Pregnancy-Specific Conditions

• Intrahepatic cholestasis of pregnancy (ICP): Diagnosed by serum bile acid level >10 μmol/L in the setting of pruritus, typically during second or third trimester; gastrointestinal symptoms including nausea can occur 1
• Pre-eclampsia: Can present with nausea, vomiting, and epigastric pain in the third trimester; check blood pressure, proteinuria, and liver enzymes 1
• HELLP syndrome: Hemolysis, elevated liver enzymes, and low platelets; presents with nausea, vomiting, and right upper quadrant pain 1
• Acute fatty liver of pregnancy: Rare but serious condition presenting in third trimester with nausea, vomiting, and liver dysfunction 1

Gastrointestinal Causes

• Gastroesophageal reflux disease (GERD): Common in pregnancy due to hormonal and physiological changes; symptoms worsen with meals 1
• Gastroparesis: Delayed gastric emptying can cause postprandial vomiting 1
• Peptic ulcer disease: Consider if associated with epigastric pain 1
• Cholelithiasis/cholecystitis: Gallbladder disease is common in pregnancy; presents with postprandial right upper quadrant pain and vomiting 1, 4
• Pancreatitis: Can be related to gallstones; presents with severe abdominal pain and vomiting 1
• Small bowel obstruction: Consider if associated with abdominal distension and constipation 1

Other Causes

• Urinary tract infection/pyelonephritis: Can cause nausea and vomiting in pregnancy 4
• Diabetic ketoacidosis: If patient has gestational or pre-existing diabetes 4
• Hyperthyroidism: Can cause persistent nausea and vomiting 4
• Central nervous system pathology: Headaches, visual changes, or neurological symptoms suggest intracranial causes 4

Diagnostic Approach

Initial Assessment

• Assess severity using the PUQE score: Mild (≤6), moderate (7-12), severe (≥13) 5, 3
• Evaluate for signs of hyperemesis gravidarum: Weight loss >5% of prepregnancy weight, dehydration, electrolyte imbalances 5, 2
• Check vital signs: Blood pressure, temperature, heart rate to assess for pre-eclampsia, infection, or dehydration 1

Pertinent History Elements

• Timing of vomiting: Immediately postprandial suggests gastroparesis or obstruction; delayed suggests other causes 4
• Associated symptoms: Pruritus (ICP), right upper quadrant pain (gallbladder disease), headache/visual changes (pre-eclampsia), fever (infection) 1, 4
• Dietary triggers: Fatty foods suggest biliary disease 1
• Previous gastrointestinal history: Pre-existing conditions may be exacerbated by pregnancy 1

Laboratory and Imaging Workup

• Basic metabolic panel: Electrolytes, renal function, glucose 5, 2
• Liver function tests: Elevated transaminases occur in 40-50% of hyperemesis gravidarum cases but also suggest ICP, pre-eclampsia, HELLP, or acute fatty liver 2
• Complete blood count: Assess for anemia, thrombocytopenia (HELLP) 1
• Serum bile acids: If pruritus present, to evaluate for ICP 1
• Urinalysis and culture: Rule out urinary tract infection 4
• Right upper quadrant ultrasound: If biliary disease suspected; safe in pregnancy 1
• Thyroid function tests: If hyperthyroidism suspected 4

Critical Red Flags Requiring Urgent Evaluation

• Persistent liver chemistry abnormalities despite symptom resolution warrant investigation for another etiology 2
• Severe abdominal pain, fever, or peritoneal signs suggest surgical emergency 1
• Neurological symptoms or severe headache with hypertension suggest pre-eclampsia/eclampsia 1

Management Approach

If Persistent NVP/Hyperemesis Gravidarum Confirmed

• Early treatment may reduce progression to hyperemesis gravidarum 1, 2
• Stepwise pharmacologic treatment: Vitamin B6 (10-25 mg every 8 hours) plus doxylamine; if inadequate, add ondansetron, metoclopramide, or promethazine 1, 5
• Intravenous hydration and electrolyte replacement for moderate to severe cases 5, 2
• Thiamine supplementation to prevent Wernicke encephalopathy 2
• Intravenous glucocorticoids may be required in severe refractory cases 1, 5

If Alternative Diagnosis Identified

• Procedures, medications, and interventions to optimize maternal health should not be withheld solely because a patient is pregnant 1
• Endoscopic procedures (e.g., ERCP for choledocholithiasis) may be performed during pregnancy for urgent indications 1
• Cholecystectomy is safe during pregnancy; laparoscopic approach is standard of care 1
• Coordination of care by a multidisciplinary team at a tertiary care center is recommended for complex conditions 1, 2

Common Pitfalls

• Assuming all vomiting in pregnancy is NVP without considering the atypical timing at 30 weeks 2
• Overlooking serious pregnancy-specific liver diseases that present with vomiting in the third trimester 1
• Delaying necessary diagnostic procedures or treatments due to pregnancy concerns 1
• Failing to provide adequate thiamine supplementation in severe cases, risking Wernicke encephalopathy 2