Gestational Diabetes Risk Calculator Formula

Understand the math behind the gestational diabetes risk calculator. Each variable explained with a worked example.

Use the Gestational Diabetes Risk Calculator

Formulas Used

Risk Score

risk_score = age_score + bmi_score + family_diabetes * 2 + previous_gdm * 3

Estimated Risk

est_risk_pct = min(2 + (age_score + bmi_score + family_diabetes * 2 + previous_gdm * 3) * 3, 50)

Variables

VariableDescriptionDefault
ageAge(years)30
pre_bmiPre-Pregnancy BMI25
family_diabetesFamily History of Diabetes0
previous_gdmPrevious Gestational Diabetes0
age_scoreDerived value= age >= 35 ? 2 : (age >= 30 ? 1 : 0)calculated
bmi_scoreDerived value= pre_bmi >= 30 ? 3 : (pre_bmi >= 25 ? 1 : 0)calculated

How It Works

Gestational Diabetes Risk Factors

Gestational diabetes mellitus (GDM) affects 2-10% of pregnancies in the US.

Risk Factor Scoring

| Factor | Points | |---|---| | Age 30-34 | 1 | | Age 35+ | 2 | | BMI 25-29.9 | 1 | | BMI 30+ | 3 | | Family history | 2 | | Previous GDM | 3 |

Risk Levels

| Score | Risk | |---|---| | 0-2 | Low | | 3-5 | Moderate | | 6+ | High |

Worked Example

A 30-year-old with BMI 25, no family history, no previous GDM.

age = 30pre_bmi = 25family_diabetes = 0previous_gdm = 0
  1. 01Age score = 1 (age 30-34)
  2. 02BMI score = 1 (BMI 25-29.9)
  3. 03Family history = 0
  4. 04Previous GDM = 0
  5. 05Total = 2 (Low risk)
  6. 06Estimated risk = 2 + 2 x 3 = 8%

Ready to run the numbers?

Open Gestational Diabetes Risk Calculator