Gestational Diabetes Calculator

Assess gestational diabetes risk factors and check glucose values against thresholds.

About Gestational Diabetes Calculator

Diagnostic thresholds for gestational diabetes differ between guidelines, so the same values can be diagnostic under one and not another. Risk factors determine screening timing rather than diagnosis. Gestational diabetes is frequently asymptomatic, which is why screening is offered on the basis of risk factors rather than symptoms.

Formula

Gestational Diabetes

Risk factors are scored, and glucose values compared against commonly cited diagnostic thresholds

fasting threshold: Commonly 5.6 mmol/L, though guidelines differ
OGTT: Oral glucose tolerance test, the standard diagnostic method

Worked example

With the default values below, Gestational Diabetes Calculator returns Risk Factor Score of 3. Change any input above and every figure here is recalculated in your browser.

Inputs used

Pre-pregnancy body mass indexaccepts 14–55 kg/m2: 28 kg/m2
Maternal ageaccepts 15–55 years: 34 years
Additional risk factors presentaccepts 0–6: 1
Fasting glucoseaccepts 2–15 mmol/L: 5.4 mmol/L
Two hour glucoseaccepts 2–25 mmol/L: 8.2 mmol/L

Results

Risk Factor Score: 3
Risk Band: Moderate risk
Fasting Value at or Above the Common Threshold: No
Two Hour Value at or Above the Common Threshold: Yes
Interpretation: One or more values reach commonly used thresholds — this requires clinical review

Step by step

1Values used
2Gestational Diabetes
3Risk Factor Score= 3
4Risk Band= Moderate risk
5Fasting Value at or Above the Common Threshold= No
6Two Hour Value at or Above the Common Threshold= Yes
7Interpretation= One or more values reach commonly used thresholds — this requires clinical review

Assumptions and limits

The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
This reproduces a published formula for educational and reference use only. It is not a diagnostic tool, does not account for individual clinical context, and must not be used to make or change treatment decisions. Clinical assessment by a qualified healthcare professional is always required. Thresholds vary between national guidelines and this cannot diagnose gestational diabetes. Pregnancy care and glucose testing must be managed by your maternity team. Contact them promptly with any concern about your pregnancy.
This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

This reproduces a published formula for educational and reference use only. It is not a diagnostic tool, does not account for individual clinical context, and must not be used to make or change treatment decisions. Clinical assessment by a qualified healthcare professional is always required. Thresholds vary between national guidelines and this cannot diagnose gestational diabetes. Pregnancy care and glucose testing must be managed by your maternity team. Contact them promptly with any concern about your pregnancy.

Frequently Asked Questions

How is Gestational Diabetes calculated?

Risk factors are scored, and glucose values compared against commonly cited diagnostic thresholds Diagnostic thresholds for gestational diabetes differ between guidelines, so the same values can be diagnostic under one and not another. Risk factors determine screening timing rather than diagnosis.

Why does Gestational Diabetes matter?

Gestational diabetes is frequently asymptomatic, which is why screening is offered on the basis of risk factors rather than symptoms.

What values do I need to enter?

This calculator takes 5 inputs: Pre-pregnancy body mass index, Maternal age, Additional risk factors present, Fasting glucose, Two hour glucose. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.