Women's HealthPending review

Hyperemesis gravidarum

An exaggerated response to rising beta-hCG in early pregnancy drives vomiting so severe and persistent that it causes dehydration, electrolyte disturbance and starvation ketosis, a diagnosis of exclusion that can rapidly become an emergency.

In a nutshell

Rising beta-hCG in early pregnancy drives nausea and vomiting; hyperemesis gravidarum is the severe, intractable extreme of this normal mechanism. Persistent vomiting prevents oral intake, causing dehydration, electrolyte disturbance and starvation ketosis, and it is a diagnosis of exclusion once other causes of vomiting have been ruled out.

Classic presentation

Severe, persistent vomiting in the first trimester with over 5% weight loss, dehydration and ketonuria, unable to keep down food or fluids.

Key points

Very high hCG states (multiple pregnancy and molar pregnancy) increase the risk and severity of hyperemesis; ultrasound should be used to exclude these.

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Educational content pending clinical review. Not medical advice.