Hyperemesis gravidarum
Hyperemesis gravidarum (HG) is severe nausea and vomiting in pregnancy that interferes with normal eating and drinking and can cause dehydration, weight loss and electrolyte problems. It is much more severe than typical pregnancy nausea.
At a glance
Quick facts
- Category
- Pregnancy complication
- Main feature
- Severe persistent nausea / vomiting
- Potential effects
- Dehydration and weight loss
- Usual onset
- Early pregnancy
- Treatment
- Antiemetics + hydration
- Hospital care
- Sometimes required
Dr. Fitsum Admasu Tinsae
General Medicine · Public Health · Digital Health
Reviewed for clinical accuracy, clarity and practical public-health context.
Names & terminology
How this entity may be named or searched
- Hyperemesis gravidarum (HG)
- Severe nausea and vomiting in pregnancy with major functional, nutritional or hydration impact.
- Nausea and vomiting of pregnancy (NVP)
- The broader spectrum of pregnancy-related nausea and vomiting.
- Morning sickness
- Common lay term, but symptoms can occur at any time of day.
- PUQE score
- A validated symptom score that can help quantify nausea and vomiting severity.
Structured entity profile
Clinical profile
Overview
Nausea and vomiting are common in pregnancy, but hyperemesis gravidarum is a severe form that disrupts normal eating and drinking and can cause dehydration, weight loss and metabolic disturbance. RCOG estimates HG affects about 0.3% to 3.6% of pregnancies. [1]
Symptoms usually begin in early pregnancy. RCOG defines pregnancy nausea/vomiting as beginning before 16 weeks when other causes have been excluded, and the updated guideline emphasizes clinical severity rather than dismissing symptoms as routine “morning sickness.” [1]
Symptoms and warning signs
SYMPTOM MATRIX
HG is severe enough to impair hydration, nutrition or daily function
Persistent inability to drink, fainting or markedly reduced urine output should prompt urgent assessment.
- Persistent nausea
- Frequent vomiting
- Difficulty keeping down food or fluids
- Weight loss
- Marked interference with daily life
- Dizziness or weakness
- Dry mouth
- Reduced urination
- Electrolyte abnormalities
- Vitamin deficiency risk
- Unable to keep fluids down
- Fainting or severe dizziness
- Very little urine
- Confusion or severe weakness
- Vomiting blood or severe abdominal pain
Severe dehydration and electrolyte disturbance in pregnancy require prompt medical treatment.
Diagnosis
Assessment includes symptom timing and severity, weight change, hydration, urine output and physical examination. Clinicians consider other causes of vomiting such as infection, gastrointestinal disease, thyroid disease, metabolic problems and pregnancy-specific complications. [1]
Blood tests and urine testing may assess electrolytes, kidney function, liver abnormalities, ketones or other concerns depending on severity. Ultrasound may be used for obstetric assessment or when another pregnancy-related cause is suspected. [1]
Diagnostic pathway
Measure severity and exclude another cause of persistent vomiting
The diagnosis is clinical; investigations are guided by dehydration, weight loss and atypical features.
Urine ketones can reflect reduced intake, but hyperemesis severity should not be judged from a single ketone result alone. Source [1]
Why hyperemesis gravidarum matters
Untreated severe vomiting can cause dehydration, electrolyte imbalance, nutritional deficiency and substantial physical and psychological distress. Thiamine deficiency is a preventable serious complication when prolonged vomiting and malnutrition are present. [1]
Treatment and management
Treatment is stepwise. Antiemetics are offered according to symptom severity, effectiveness, adverse effects and patient preference. People with moderate to severe symptoms may need intravenous fluids, ideally in an ambulatory setting when clinically appropriate. [2]
Thiamine deficiency can be missed in prolonged vomiting or severely reduced intake. Thiamine should be considered before dextrose is given to a patient at risk.
Psychological and social support also matter because hyperemesis gravidarum can have a major effect on daily functioning and quality of life.
Inpatient care is considered when vomiting is severe and does not respond to primary or outpatient treatment, when dehydration or metabolic disturbance is significant, or when oral medication cannot be retained. Nutritional support and vitamin replacement may be needed in prolonged severe cases. [1] [2]
Treatment & care hub
Restore hydration, control vomiting and protect nutrition
The right setting ranges from community care to inpatient treatment depending on severity and response.
Reduce nausea and vomiting
Medication is individualized according to effectiveness, adverse effects and pregnancy context.
Replace fluids and electrolytes
IV fluids are used when oral intake is insufficient or dehydration is clinically significant.
Prevent deficiency
Thiamine and nutritional support are considered when vomiting and poor intake are prolonged.
Monitor closely
Hospital care is appropriate when severe symptoms persist or outpatient management is unsafe or ineffective.
How long does HG last?
Many people improve as pregnancy progresses, but symptoms can persist beyond 20 weeks and, in severe cases, throughout pregnancy. Follow-up should include hydration, nutrition, weight, mental well-being and the ability to function at home. [1]
Pregnancy prevalence
Hyperemesis gravidarum affects about 0.3% to 3.6% of pregnancies
RCOG describes HG as a severe and highly disruptive form of nausea and vomiting in pregnancy.
Common questions
Frequently asked questions
No. HG is much more severe and can prevent normal eating and drinking, cause dehydration and weight loss, and substantially impair daily functioning.
Urgent assessment is appropriate when fluids cannot be kept down, urine output falls markedly, fainting occurs, or there is severe weakness, confusion, abdominal pain or blood in vomit.
Treatment can include antiemetics, oral or intravenous fluids, electrolyte correction, vitamin support and inpatient care when symptoms are severe or persistent.
No. Many improve later in pregnancy, but symptoms can persist beyond 20 weeks and sometimes throughout pregnancy.
Yes. Prolonged severe vomiting can cause weight loss and vitamin or electrolyte deficiencies, so nutrition and hydration need monitoring.
Sources
- RCOG — The Management of Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum — Green-top Guideline No.69
- NICE — Antenatal care (NG201) — nausea and vomiting recommendations
This article is based on trusted medical sources and has undergone clinician review. It is not a substitute for personalized medical advice.
With persistent vomiting, the complications that concern me most are dehydration and electrolyte disturbance, especially when oral intake has been poor for a prolonged period.