Clinical Overview of Hyperemesis Gravidarum for Trainees

OBSTETRICS & GYNECOLOGY

Hyperemesis Gravidarum

A Comprehensive Clinical Overview

For Medical Students & Trainees

Prepared for Academic Use · 2026

Contents

01

Understanding Hyperemesis Gravidarum

Definition, epidemiology, pathophysiology, risk factors

02

Diagnosis & Assessment

Signs & symptoms, diagnostic criteria, complications

03

Treatment Strategies & Care Pathways

Non-pharmacological, pharmacological, IV therapy, protocols

04

Long-Term Outcomes, Support & Education

Prognosis, psychological impact, patient education

01

SECTION 01

Understanding

Hyperemesis Gravidarum

Definition · Epidemiology · Pathophysiology · Risk Factors

Definition & Epidemiology

01

Definition

HG is a severe form of nausea and vomiting of pregnancy (NVP)

<strong style='color: #1e2a2a; font-weight: 700;'>Characterized by:</strong> persistent vomiting, >5% pre-pregnancy weight loss, dehydration, electrolyte/metabolic disturbances

<strong style='color: #1e2a2a; font-weight: 700;'>Onset:</strong> typically weeks 4–10 of gestation

<strong style='color: #1e2a2a; font-weight: 700;'>Distinct from morning sickness:</strong> debilitating, requires medical intervention

<strong style='color: #1e2a2a; font-weight: 700;'>ICD-10:</strong> O21.0 – O21.1

Epidemiology

Affects 0.3–3% of pregnancies worldwide

Leading cause of hospitalization in first trimester

<strong style='color: #1e2a2a; font-weight: 700;'>Recurrence rate:</strong> 15–81% in subsequent pregnancies

<strong style='color: #1e2a2a; font-weight: 700;'>More common in:</strong> primigravidas, multiple gestations, molar pregnancy, female fetus

<strong style='color: #1e2a2a; font-weight: 700;'>Global burden:</strong> significant economic & psychosocial impact

OBSTETRICS & GYNECOLOGY

Pathophysiology

SECTION 01

Hormonal Triggers

Mediating Pathways

Final Clinical Outcome

↑ hCG Levels

Peak at 8–12 weeks, correlates with severity

↑ Estrogen (E2)

Stimulates emesis center, nausea amplification

Progesterone

Reduces GI motility, delayed gastric emptying

Hypothalamic-Pituitary Axis

Dysregulation of appetite and satiety signals

H. pylori Infection

Associated in subset of patients, may exacerbate symptoms

Intractable Vomiting

Dehydration

Metabolic Derangement

Nutritional Deficiency

Multifactorial etiology — no single mechanism fully established.

Risk Factors

01

Obstetric & Pregnancy Factors

Primigravida

Multiple gestation (twins/triplets)

Molar pregnancy (hydatidiform mole)

Female fetal sex

Previous history of HG

History of NVP in prior pregnancies

Personal & Medical Factors

Personal/family history of HG

Helicobacter pylori infection

History of motion sickness

Hyperthyroid disorders

Psychological factors (anxiety, stress)

Low socioeconomic status

⚠ Clinical Pearl: A prior pregnancy complicated by HG is the strongest predictor of recurrence in future pregnancies.

SECTION 02

Diagnosis &

Assessment

Signs & Symptoms · Diagnostic Criteria · Complications

Signs & Symptoms

02

Gastrointestinal

Persistent, intractable nausea

Vomiting >3–4 times/day

Inability to tolerate oral intake

Ptyalism (excessive salivation)

Epigastric pain / heartburn

Weight loss >5% of pre-pregnancy weight

Systemic / Dehydration

Severe dehydration

Tachycardia

Hypotension / orthostatic changes

Oliguria / dark urine

Dry mucous membranes, poor skin turgor

Ketonuria

Neurological / Metabolic

Weakness and fatigue

Headache and dizziness

Wernicke's encephalopathy (thiamine deficiency — rare)

Hyponatremia symptoms (confusion)

Hypokalemia (muscle cramps, weakness)

Metabolic alkalosis

⚠ Red Flag: Neurological symptoms suggest Wernicke's encephalopathy — administer thiamine BEFORE IV dextrose.

Diagnostic Criteria & Assessment

02

No universally accepted single diagnostic test — diagnosis is CLINICAL

Nausea and vomiting starting before 10 weeks gestation

>5% loss of pre-pregnancy body weight

Ketonuria (2+ on dipstick)

Exclusion of other causes (UTI, gastroenteritis, appendicitis, thyroid disease)

PUQE Scale (Pregnancy-Unique Quantification of Emesis)

Nausea duration per day (1–5 pts)

Episodes of vomiting per day (1–5 pts)

Episodes of retching per day (1–5 pts)

Required Investigations

ketones, specific gravity

haemoconcentration, raised Hct

hyponatremia, hypokalemia

raised transaminases (in 40–50%)

gestational hyperthyroidism

confirm viable pregnancy, rule out molar

hCG cross-reactivity

Complications

02

Maternal Complications

Severe:

Wernicke's Encephalopathy — thiamine (B1) deficiency → confusion, ophthalmoplegia, ataxia

Central pontine myelinolysis — rapid sodium correction

Mallory-Weiss tear — forceful vomiting

Splenic avulsion / esophageal rupture (rare)

Metabolic:

Hyponatremia, Hypokalemia

Metabolic alkalosis / acidosis

Hypophosphatemia (refeeding syndrome risk)

Acute kidney injury (dehydration)

Nutritional:

Thiamine (B1) deficiency

Vitamin K deficiency → coagulopathy

Zinc & folate deficiency

Fetal & Obstetric Complications

Intrauterine growth restriction (IUGR)

Low birth weight

Small for gestational age (SGA)

Preterm birth (in severe cases)

Increased risk of fetal neurodevelopmental issues (Wernicke's-related)

Pregnancy termination requested (in severe uncontrolled HG)

⚠ Psychological impact:

Depression, anxiety, and PTSD are significant — up to 50% of women with HG report psychological distress.

03

SECTION 03

Treatment Strategies

& Care Pathways

Non-Pharmacological · Pharmacological · IV Therapy · Clinical Protocols

Non-Pharmacological Management

03

Dietary Modifications

Small, frequent meals every 1–2 hours

Bland, low-fat, high-carbohydrate foods

Avoid triggers: spicy, fatty, strong-smelling foods

Cold foods preferred (less odour)

Ginger: <b>250mg QID</b> — evidence-based, safe in pregnancy

Hydration & Rest

Oral rehydration: small frequent sips

Avoid large fluid volumes at once

Rest in cool, well-ventilated rooms

Avoid lying down immediately after eating

Elevation of head of bed

Psychological Support

Reassurance and validation of symptoms

CBT / counselling referral if indicated

Peer support groups (e.g., Pregnancy Sickness Support)

Reduce triggers: stress, anxiety, sensory overload

Complementary Therapies

Acupressure: P6 (Nei Kuan) wristbands

Acupuncture (limited evidence)

Hypnotherapy (limited evidence)

Vitamin B6 (Pyridoxine): <b>10–25mg TID</b> — first-line supplement

Pharmacological Treatment

03

Step 1

First-Line Antiemetics

Pyridoxine (Vitamin B6) ± Doxylamine

safe, evidence-based, first choice

Ginger supplements

adjunct, well-tolerated

Antihistamines:

Promethazine, Cyclizine, Dimenhydrinate

Step 2

Second-Line Agents

Metoclopramide 10mg TDS

dopamine antagonist,

caution: extrapyramidal effects

Prochlorperazine

phenothiazine antiemetic, oral or IM

Ondansetron (5-HT3 antagonist)

effective but avoid in 1st trimester if possible (teratogenicity debate); use if benefits > risks

Step 3

Third-Line / Severe Cases

Corticosteroids:

Methylprednisolone / Hydrocortisone IV — reserved for refractory cases; taper and switch to oral

Chlorpromazine

sedating phenothiazine for severe inpatient use

Total Parenteral Nutrition (TPN)

last resort, rare

All medications should be prescribed with consideration of gestational age, teratogenic risk, and benefit-risk discussion with the patient.

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IV Therapy & Inpatient Rehydration

03

Indications for Admission

Inability to maintain oral hydration

Weight loss >5% despite outpatient management

Ketonuria 2+ or 3+

Electrolyte disturbances (K+ <3.0, Na+ <130)

Signs of dehydration (tachycardia, hypotension, oliguria)

Neurological symptoms (Wernicke's risk)

IV Fluid Regimen

Normal Saline (0.9% NaCl) OR Hartmann's — FIRST LINE

AVOID dextrose

until thiamine given (Wernicke's risk)

Potassium replacement: add KCl to IV fluids as indicated

Thiamine (B1): 100mg IV/IM before any glucose-containing fluids

Monitor electrolytes 12–24 hourly

Nutritional Support Ladder

Oral Diet

Preferred — small, frequent meals

Enteral Nutrition (NG)

Nasogastric tube feeding (2nd line, better than TPN)

Enteral Nutrition (NJ)

Nasojejunal tube — if NG not tolerated

Total Parenteral Nutrition (TPN)

LAST RESORT — high infection/complication risk

Evidence supports enteral over parenteral nutrition — lower risk of complications.

Care Pathway & Clinical Protocol

03

STAGE 1

Initial Presentation

Clinical assessment: history, examination, PUQE score

Investigations: urine dipstick, bloods (FBC, U&E, LFTs, TFTs), USS

Confirm diagnosis & severity grading

STAGE 2

Mild-Moderate HG

Outpatient management

Dietary advice + lifestyle modifications

First-line antiemetics: Pyridoxine ± Doxylamine / Antihistamines

Review in 48 hours

STAGE 3

Severe / Not Responding

Admit to hospital

IV rehydration (Normal Saline) + electrolyte replacement

IV Thiamine BEFORE glucose

IV antiemetics: Metoclopramide / Ondansetron

Daily monitoring: weight, electrolytes, urine output

STAGE 4

Refractory / Severe Complications

MDT involvement: Obstetrics + Gastroenterology + Dietitian + Psychology

Consider corticosteroids

Enteral nutrition (NG/NJ)

TPN only as last resort

Psychological support + birth planning discussion

Follow local protocol in line with RCOG Green-top Guideline No. 69

04

SECTION 04

Long-Term Outcomes,

Support & Education

Prognosis · Psychological Impact · Patient Support · Education

Long-Term Outcomes & Prognosis

04

Maternal Outcomes

<div style="display: flex; flex-direction: column; gap: 16px; color: #3f4c4a; font-size: 20px; line-height: 1.5; font-weight: 400; font-family: 'Inter', sans-serif;"> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #4a7c6f; font-size: 26px; line-height: 1;">•</div> <div>Most cases resolve by 20 weeks gestation</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #4a7c6f; font-size: 26px; line-height: 1;">•</div> <div>~10% of women have symptoms persisting throughout pregnancy</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #4a7c6f; font-size: 26px; line-height: 1;">•</div> <div>Increased risk of postpartum depression</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #4a7c6f; font-size: 26px; line-height: 1;">•</div> <div>PTSD reported in women with severe HG</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #4a7c6f; font-size: 26px; line-height: 1;">•</div> <div>Negative impact on relationship and employment</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #4a7c6f; font-size: 26px; line-height: 1;">•</div> <div>Some women terminate pregnancies due to severity</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #4a7c6f; font-size: 26px; line-height: 1;">•</div> <div>Long-term nutritional deficiencies if severe and prolonged</div> </div> </div>

Fetal Outcomes

<div style="display: flex; flex-direction: column; gap: 16px; color: #3f4c4a; font-size: 20px; line-height: 1.5; font-weight: 400; font-family: 'Inter', sans-serif;"> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #5d8e82; font-size: 26px; line-height: 1;">•</div> <div>Generally good fetal outcome in well-managed HG</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #5d8e82; font-size: 26px; line-height: 1;">•</div> <div>Risk of IUGR/LBW in severe, poorly controlled cases</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #5d8e82; font-size: 26px; line-height: 1;">•</div> <div>Slight increase in preterm birth</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #5d8e82; font-size: 26px; line-height: 1;">•</div> <div>Possible association with neurodevelopmental outcomes (conflicting evidence)</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #5d8e82; font-size: 26px; line-height: 1;">•</div> <div>Wernicke's-related fetal neurological damage (very rare)</div> </div> </div>

Recurrence & Future Pregnancies

<div style="display: flex; flex-direction: column; gap: 16px; color: #3f4c4a; font-size: 20px; line-height: 1.5; font-weight: 400; font-family: 'Inter', sans-serif;"> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #c86b5e; font-size: 26px; line-height: 1;">•</div> <div>Recurrence rate: 15–81% in subsequent pregnancies</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #c86b5e; font-size: 26px; line-height: 1;">•</div> <div>Earlier onset in subsequent pregnancies (may begin before missed period)</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #c86b5e; font-size: 26px; line-height: 1;">•</div> <div>Pre-emptive counselling recommended</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #c86b5e; font-size: 26px; line-height: 1;">•</div> <div>Consider early antiemetic prescription in next pregnancy</div> </div> <div style="display: flex; gap: 14px; align-items: flex-start;"> <div style="color: #c86b5e; font-size: 26px; line-height: 1;">•</div> <div>Pre-conception folic acid and vitamin optimization</div> </div> </div>

Prognosis is generally excellent with appropriate management — emphasis on early recognition and intervention.

Support & Patient Education

04

Psychosocial Support

For the patient

Validate and acknowledge suffering — HG is NOT psychological in origin

Early referral to counsellor/psychologist if anxiety/depression present

Connect to peer support networks (e.g. Pregnancy Sickness Support UK)

MDT approach: midwife, dietitian, social worker

For the family/partner

Educate family about severity and legitimacy of condition

Encourage practical support at home

Address employment/financial concerns (sick leave entitlement)

Patient Education Points

What patients should know

HG is a medical condition, not "just morning sickness"

It is NOT caused by stress or poor diet

Treatment options are safe and effective

When to seek help: unable to keep fluids down >24h, dark urine, dizziness

Medication safety in pregnancy — reassurance

Future pregnancy planning: discuss with clinician early

Resources: RCOG patient leaflet, PSS helpline, online communities

<strong>Learning Points:</strong> Early diagnosis &nbsp;|&nbsp; Stepwise treatment &nbsp;|&nbsp; IV thiamine BEFORE glucose &nbsp;|&nbsp; MDT approach &nbsp;|&nbsp; Psychological support &nbsp;|&nbsp; Recurrence counselling

SUMMARY

Key Clinical Takeaways

HG is severe, debilitating NVP affecting 0.3–3% of pregnancies

Diagnosis is clinical — use PUQE scale to assess severity

Stepwise management: dietary → antiemetics → IV therapy → MDT

Always give IV Thiamine BEFORE glucose to prevent Wernicke's

Psychosocial support is integral — acknowledge patient suffering

Questions & Discussion

References: RCOG Green-top Guideline No. 69 | UpToDate | SOGC Clinical Practice Guideline