Stillbirth Risk Calculator – Fetal Mortality Risk
Assess your stillbirth risk based on maternal age, gestational age, and clinical risk factors using validated epidemiological models.
Enter maternal and pregnancy details to receive a relative risk score, risk category, and evidence-based recommendations for prenatal monitoring.
Stillbirth Risk Calculator – Fetal Mortality Risk
Assess your stillbirth risk based on maternal age, gestational age, and clinical risk factors using validated epidemiological models.
About the Stillbirth Risk Calculator
Stillbirth — defined as fetal death at or after 20 weeks of gestation — affects approximately 2–3 per 1,000 pregnancies in high-income countries, and considerably more in low- and middle-income settings. Despite advances in obstetric care, stillbirth rates have declined more slowly than infant mortality, making prevention a priority for perinatal medicine. This calculator estimates relative stillbirth risk by combining validated epidemiological risk factors into a composite score, helping expectant parents and clinicians understand which factors warrant closer monitoring.
Maternal age is one of the best-established risk factors. Women under 20 and over 35 have consistently higher stillbirth rates than women aged 20–34, with risk rising steeply after age 40. This relationship reflects the cumulative effects of aging on the placenta, increased chromosomal abnormality rates in the fetus, and a higher prevalence of medical comorbidities in older mothers. Gestational age also matters: stillbirth risk per ongoing pregnancy is lowest in the second trimester and increases in the post-term period, which is why most guidelines recommend induction of labor by 41–42 weeks.
A history of previous stillbirth is the single most powerful predictor of recurrence, with relative risks ranging from 2- to 10-fold above baseline depending on the cause. The recurrence risk is highest when the original cause was unexplained or related to a persistent underlying condition such as antiphospholipid syndrome or a uterine anomaly. Women with prior stillbirth require detailed counseling and enhanced surveillance in subsequent pregnancies.
Medical conditions significantly elevate risk. Preeclampsia and its severe forms impair placental perfusion and are responsible for approximately 10–20% of stillbirths attributable to a known cause. Both pre-existing and gestational diabetes are associated with 2- to 3-fold increased risk, largely through fetal overgrowth, polyhydramnios, and uteroplacental dysfunction. Chronic hypertension compounds risk similarly. Fetal growth restriction (FGR) — where the baby is not growing adequately for gestational age — is the strongest acute predictor of imminent stillbirth; severe FGR (estimated fetal weight below the 3rd percentile) demands urgent specialist evaluation.
Lifestyle factors including smoking and obesity each independently increase stillbirth risk by approximately 2-fold. Smoking impairs fetal oxygenation through carbon monoxide exposure and vasoconstriction; quitting at any point in pregnancy reduces risk. Obesity contributes through metabolic dysfunction, uteroplacental insufficiency, and increased rates of pregnancy complications. Multiple pregnancies (twins, triplets) carry inherently higher risks due to inter-twin vascular connections, preterm delivery, and selective growth restriction.
This calculator uses a point-based risk-scoring approach derived from published relative risk estimates and translates the cumulative score into an approximate absolute risk range and a risk category (Low, Moderate, High, Very High). It is intended for educational and awareness purposes only. Absolute risk numbers are population-based estimates and cannot account for individual clinical nuances; a formal risk assessment by a qualified obstetric provider is always required.
Stillbirth risk assessment examples
These scenarios illustrate how different combinations of risk factors translate into risk categories.
| Patient profile | Risk category | Key factors |
|---|---|---|
| Age 26, 28 weeks, no risk factors, white | Low Risk | Young healthy primigravida with no complications; routine prenatal care is appropriate. |
| Age 32, 35 weeks, gestational diabetes, Hispanic | Moderate Risk | Single additional risk factor (gestational diabetes); enhanced monitoring recommended. |
| Age 38, 36 weeks, previous stillbirth, preeclampsia, pre-existing diabetes, hypertension, obese, smoking | Very High Risk | Multiple high-impact risk factors; intensive specialist care and frequent fetal surveillance required. |
| Age 34, 32 weeks, severe fetal growth restriction, placenta previa | High Risk | Severe FGR and placental pathology are acute risk indicators; immediate specialist consultation needed. |
How to use the Stillbirth Risk Calculator
- Enter the mother's current age in years and the current gestational age in weeks.
- Select the appropriate option for each clinical risk factor from the dropdown menus: previous stillbirth history, preeclampsia/eclampsia status, diabetes type, hypertension severity, obesity, smoking, multiple pregnancy, placental problems, fetal growth status, and ethnicity.
- Click 'Calculate Risk' to view the risk score, risk category, approximate risk percentage range, and a clinical recommendation.
- Share the results with your obstetrician or midwife for interpretation within your individual clinical context and to plan appropriate monitoring.
- Use the Reset button to evaluate a different profile or to update your assessment as pregnancy progresses.
Stillbirth Risk Calculator FAQ
What is defined as a stillbirth?
A stillbirth is defined as the death of a baby in the womb at or after 20 weeks of pregnancy in most countries (some use 24 weeks as the threshold). The term distinguishes late pregnancy loss from miscarriage (loss before 20 weeks) and neonatal death (death within the first 28 days after birth). Globally, an estimated 2 million stillbirths occur each year.
What is the most common cause of stillbirth?
In high-income countries, approximately 25–35% of stillbirths remain unexplained after full investigation. Among identified causes, placental dysfunction is the most common, accounting for about 25–30% of cases. Other leading causes include fetal growth restriction, congenital anomalies, umbilical cord complications, infection, and maternal medical conditions such as preeclampsia and diabetes.
Can stillbirth be prevented?
Not all stillbirths are preventable, but evidence-based interventions can reduce risk significantly. These include stopping smoking, achieving a healthy weight before pregnancy, managing diabetes and hypertension, attending all prenatal appointments, monitoring fetal movements daily and reporting changes promptly, and following guidelines for timely delivery when risk factors are present. For high-risk pregnancies, increased surveillance can detect deterioration before it becomes fatal.
What is fetal growth restriction and why does it matter?
Fetal growth restriction (FGR) means the baby is not growing at the expected rate for its gestational age, usually defined as an estimated fetal weight below the 10th percentile for gestational age. Severe FGR (below the 3rd percentile) is associated with a dramatically increased stillbirth risk because it often reflects impaired placental function that can deteriorate rapidly. FGR requires close surveillance with serial ultrasound scans and Doppler assessment.
Is this calculator a substitute for medical advice?
No. This calculator is an educational tool based on population-level risk estimates and is not a clinical diagnostic instrument. It cannot account for the full complexity of an individual pregnancy, including genetic factors, placental function, fetal wellbeing, or real-time clinical assessment. All stillbirth risk assessment must be performed by a qualified obstetric healthcare provider. If you have concerns about your pregnancy, contact your midwife, obstetrician, or emergency services without delay.