What are the diagnostic criteria and scoring systems for hyperemesis gravidarum?

Diagnostic Criteria and Scoring Systems for Hyperemesis Gravidarum

Hyperemesis gravidarum should be diagnosed using the Windsor definition: severe nausea and/or vomiting beginning before 16 weeks gestation, inability to eat and drink normally, and strongly limiting daily activities, with signs of dehydration being contributory—not mandatory—for diagnosis. 1

Clinical Diagnostic Criteria (Windsor Definition)

The Windsor definition represents a paradigm shift away from historic reliance on objective measures (weight loss, electrolyte abnormalities) toward patient-centered subjective criteria 1. This approach improves recognition and prevents underdiagnosis of HG.

Required elements for diagnosis:

• Timing: Symptoms begin in early pregnancy (before 16 weeks gestation) 1
• Severity: At least one symptom (nausea OR vomiting) must be severe 1
• Functional impact: Inability to eat and drink normally 1
• Activity limitation: Strongly limits daily living activities 1
• Dehydration signs: Contributory but not required for diagnosis 1

Critical exclusion: Other causes of nausea and vomiting must be ruled out 1

Validated Scoring Systems

PUQE Score (Pregnancy-Unique Quantification of Emesis)

Use the PUQE score for mild to moderate nausea and vomiting in pregnancy, but NOT for severe NVP or HG. 1

• Assesses symptoms over the previous 24 hours 1
• Classifies severity as mild, moderate, or severe 1
• Valid for monitoring treatment response in mild-moderate cases only 1
• Major limitation: PUQE misses severe disease—it classified only 58% of women reporting "nothing goes or stays down" as severe 2

HELP Score (HyperEmesis Level Prediction)

Use the HELP score for severe NVP and HG to quantify symptoms and track treatment response over time. 1

• Specifically developed and validated for HG severity assessment 1
• Available as online calculator (https://hyperemesis.org/tools/help-score/) and app 1
• Superior performance: HELP classified 92% of women reporting "nothing goes or stays down" as severe, compared to only 58% with PUQE 2
• Better identifies patients requiring intervention 2
• Can be trended over time to monitor progress 1

Laboratory Findings (Supportive, Not Diagnostic)

Do NOT use ketonuria to assess severity or make diagnostic decisions—it is not associated with HG severity or dehydration in pregnancy. 1 This is Grade A evidence (highest level) 1.

Common laboratory abnormalities (present but not required for diagnosis):

• Electrolyte disturbances: hyponatremia, hypokalemia, hypochloremia 1
• Metabolic alkalosis (or acidosis if severe) 1
• Low serum urea, raised hematocrit 1
• Abnormal thyroid function (66% of cases): biochemical thyrotoxicosis with raised free T4, suppressed TSH—does NOT require antithyroid treatment 1
• Elevated transaminases (up to 40% of cases), mild bilirubin/amylase elevation 1

Clinical Assessment Components

Obtain specific history elements:

• Quantify severity using PUQE or HELP score 1
• Document: frequency of nausea, vomiting episodes, ptyalism (hypersalivation), spitting, weight loss 1
• Assess inability to maintain oral intake 1
• Previous history of NVP/HG 1

Physical examination findings:

• Signs of dehydration (though contributory, not mandatory) 1
• Weight loss documentation 1

Common Pitfalls

1. Relying on ketonuria: This outdated criterion should be abandoned—ketonuria has no association with HG presence or severity 1, 3

2. Using PUQE for severe disease: PUQE underestimates severe HG and should not be used for hospitalized patients or those with severe symptoms 1, 2

3. Requiring objective measures: The Windsor definition intentionally moves away from mandatory weight loss or electrolyte abnormalities, which can delay diagnosis 1

4. Treating biochemical thyrotoxicosis: Elevated T4 and low TSH in straightforward HG cases resolve spontaneously and do not require antithyroid drugs 1

Practical Algorithm

1. Screen timing: Symptoms before 16 weeks gestation? If no → not HG
2. Assess severity: Use HELP score for suspected severe disease, PUQE for mild-moderate cases 1
3. Evaluate functional impact: Can patient eat/drink normally? Are daily activities severely limited? 1
4. Exclude other causes: Rule out alternative diagnoses 1
5. Check supportive labs: Electrolytes, renal function, liver enzymes, thyroid function—but do not require abnormalities for diagnosis 1
6. Ignore ketonuria: Do not factor into diagnostic or severity assessment 1