About the stillbirth risk calculator
This calculator gives an approximate, educational estimate of stillbirth risk. It starts from a population baseline stillbirth rate and multiplies that baseline by relative-risk factors for maternal age, pre-pregnancy BMI, smoking, prior stillbirth, multiple gestation, and pre-existing diabetes or chronic hypertension - a multiplicative relative-risk model widely used in perinatal epidemiology to translate population risk factors into an individual estimate.
How the estimate is built
- Baseline rate: approximately 6 stillbirths per 1,000 total births (about 1 in 167 pregnancies), a commonly cited population average for high-income countries with no additional risk factors present.
- Relative-risk multipliers: each factor you select - older maternal age, higher BMI, smoking, a prior stillbirth, a multiple pregnancy, or a chronic condition - applies a multiplier greater than 1 reflecting how much more often stillbirth occurs in pregnancies with that factor, based on published perinatal research.
- Combining factors: the multipliers are multiplied together and capped at 12 times baseline, since multiplying several independent-looking risk ratios can otherwise compound into an implausibly high number.
Putting the result in context
The output is a population-level estimate, not a prediction for any single pregnancy. It cannot see ultrasound findings, fetal movement patterns, lab results, or the many other details a clinician uses to assess an individual pregnancy. Two pregnancies with the same listed risk factors can have very different actual outcomes.
When to consult a professional
Any concern about stillbirth risk, reduced or changed fetal movement, or other pregnancy symptoms should be discussed promptly with an obstetric care provider - this calculator is an educational tool, not a substitute for clinical evaluation or emergency care.