Preeclampsia Risk Calculator Formula

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

Use the Preeclampsia Risk Calculator

Formulas Used

Risk Score

risk_score = age_risk + bmi_risk + first_pregnancy * 1 + chronic_hypertension * 3 + previous_preeclampsia * 3

Estimated Risk

est_risk_pct = min(3 + (age_risk + bmi_risk + first_pregnancy + chronic_hypertension * 3 + previous_preeclampsia * 3) * 2.5, 40)

Variables

VariableDescriptionDefault
ageAge(years)28
pre_bmiPre-Pregnancy BMI24
first_pregnancyFirst Pregnancy?1
chronic_hypertensionChronic Hypertension?0
previous_preeclampsiaPrevious Preeclampsia?0
age_riskDerived value= age >= 40 ? 2 : (age >= 35 ? 1 : 0)calculated
bmi_riskDerived value= pre_bmi >= 30 ? 2 : (pre_bmi >= 25 ? 1 : 0)calculated

How It Works

Preeclampsia Risk Factors

Preeclampsia affects 3-8% of pregnancies worldwide. It involves new-onset high blood pressure and organ damage, typically after 20 weeks of pregnancy.

Risk Factor Scoring

| Factor | Points | |---|---| | Age 35-39 | 1 | | Age 40+ | 2 | | BMI 25-29.9 | 1 | | BMI 30+ | 2 | | First pregnancy | 1 | | Chronic hypertension | 3 | | Previous preeclampsia | 3 |

Worked Example

A 28-year-old, BMI 24, first pregnancy, no hypertension history.

age = 28pre_bmi = 24first_pregnancy = 1chronic_hypertension = 0previous_preeclampsia = 0
  1. 01Age risk = 0 (under 35)
  2. 02BMI risk = 0 (under 25)
  3. 03First pregnancy = 1 point
  4. 04Total = 1
  5. 05Estimated risk = 3 + 1 x 2.5 = 6%

Ready to run the numbers?

Open Preeclampsia Risk Calculator