Hyperemesis gravidarum
Hyperemesis gravidarum is severe, persistent first-trimester vomiting causing starvation ketosis and at least a 5% loss of prepregnancy weight, distinguishing it from ordinary nausea and vomiting of pregnancy. Management follows a stepwise antiemetic ladder from doxylamine-pyridoxine through IV fluids, thiamine, and refractory-line corticosteroids.
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What this article covers
- Overview
Severe, persistent vomiting of pregnancy causing measurable harm: hyperemesis gravidarum is intractable nausea and vomiting in pregnancy, not related to another cause, that leads to starvation…
- Epidemiology
Common in a milder form, uncommon at the hyperemesis threshold: nausea and vomiting affect the large majority of pregnancies, but only a small minority progress to the weight-loss, ketosis-defined severity of hyperemesis gravidarum.
- Risk factors
Multiple gestation: twins or higher-order pregnancy from higher placental mass and beta-hCG.
- Pathophysiology
Beta-hCG rise as the proximate trigger: beta-hCG peaks over the same first-trimester window hyperemesis gravidarum presents, and higher beta-hCG states (multiples, molar pregnancy) produce more severe disease.
- Clinical features
Intractable nausea and vomiting with objective weight loss: the defining feature is first-trimester vomiting severe enough to produce at least a 5% loss of prepregnancy body weight.
- Differential diagnosis
Molar pregnancy (hydatidiform mole) or gestational trophoblastic neoplasia: markedly elevated beta-hCG, often 100,000 mIU/mL, uterine size greater than dates, and a "snowstorm" appearance with no…
- Diagnosis
Clinical diagnosis based on severity, not a laboratory test: hyperemesis gravidarum is diagnosed clinically by intractable first-trimester vomiting producing at least 5% prepregnancy weight loss with…
- Management
Step 1, mild-to-moderate symptoms with tolerated oral intake: dietary changes plus doxylamine-pyridoxine.
- Complications
Wernicke encephalopathy: thiamine deficiency from prolonged vomiting, presenting with gait ataxia and oculomotor dysfunction; a medical emergency requiring immediate high-dose thiamine before or with any dextrose.
- Prognosis
Favorable with appropriate step-up treatment: most cases improve with the antiemetic ladder and fluid/electrolyte correction, without progression to severe complications.
- Prevention
Start prophylactic doxylamine-pyridoxine at the first sign of nausea in a patient with a prior episode: 1 to 2 tablets (10 mg/10 mg each) orally at bedtime, before weight loss or ketosis develop…
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