Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
Hyperemesis gravidarum
Obstetrics and gynaecology · UK scope · Sources checked 7 Sept 2026 · Clinical review pending
!Neurological change during prolonged vomitingConfusion, gait disturbance or abnormal eye movements after poor intake may represent thiamine deficiency with Wernicke encephalopathy, even when all three features are not present.
Action: Arrange immediate hospital assessment, give treatment-dose intravenous thiamine through the acute neurological protocol, correct associated magnesium deficiency and do not wait for imaging or a vitamin result. Give thiamine before carbohydrate where feasible, but never delay emergency treatment of hypoglycaemia.
Synopsis
Recognise disabling pregnancy vomiting, restore fluid and nutritional safety, and escalate antiemetic treatment while investigating features that suggest a different diagnosis.
- Hyperemesis is severe pregnancy nausea and vomiting that prevents normal eating and drinking and substantially impairs daily life.
- Quantify symptoms with PUQE or HELP alongside oral intake, weight trajectory, hydration, function and psychological distress.
- Ketonuria is not a reliable measure of dehydration or disease severity and must not determine access to treatment.
- Use oral or alternative-route antiemetics promptly; combinations from different classes may be necessary when one agent is inadequate.
- For admitted patients or severely reduced intake, provide thiamine and assess venous thrombosis and refeeding risks.
- Investigate pain, fever, neurological findings, late onset or major biochemical abnormalities for an alternative or additional disorder.
Key red flags
Inability to retain fluids or essential medicines, oliguria, syncope or marked postural symptoms requires same-day assessment for dehydration and metabolic disturbance.
New focal abdominal pain, fever, haematemesis, jaundice or vomiting that first begins after 16 weeks requires investigation beyond pregnancy sickness.
Confusion, ataxia or ophthalmoplegia during prolonged poor intake requires immediate treatment for possible Wernicke encephalopathy.
Investigation priorities
01Urea, electrolytes and creatinineFirst stepMeasure renal effect and guide safe fluid and potassium replacement.
Management branches
Initial treatmentEnable oral intake and symptom controlEarly pregnancy nausea is preventing normal meals but assessment shows no physiological instability.
- Offer practical food and fluid strategies chosen by the patient, avoiding advice that implies dietary failure caused the illness.
- Start an appropriate antihistamine or phenothiazine, or licensed doxylamine-pyridoxine; prescribe regularly and change route if tablets are not retained.
- Review response promptly, combine different drug classes when needed, and provide explicit criteria for same-day reassessment.
Key medicines
CyclizineGive 50 mg orally, intramuscularly or intravenously every 8 hours when required within a regular symptom-control plan.Sedation and anticholinergic effects matter; parenteral administration requires appropriate clinical monitoring and medication-interaction review.
MetoclopramideUse 5–10 mg orally or by appropriate parenteral route every 8 hours; maximum 30 mg daily or 0.5 mg/kg daily, whichever is lower, usually for no more than 5 days.Stop for dystonia or other extrapyramidal symptoms; administer intravenous doses slowly over at least 3 minutes.
Sources and review status5 sources · checked 7 Sept 2026 · clinical review pending+
SourcesSources and review status
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 7 Sept 2026; clinical approval remains outstanding.
Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes
Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom