VTE Risk in Pregnancy Calculator
Review pregnancy and postpartum VTE risk factors in a structured checklist that keeps stage and BMI context visible for educational use.
Stillbirth Risk Assessment Calculator
Review stillbirth-related risk factors in a simplified educational worksheet that compares selected factors with broad population baseline rates.
⚕️ Medical Disclaimer: This is an educational worksheet that combines gestational-age baseline rates with selected literature-based risk factors. It is not a validated individualized stillbirth prediction model.
weeks
years
Pre-pregnancy or early pregnancy BMI
Risk Factors (select all that apply)
Gestational-Age Baseline⧉
2.8 per 1,000
Population baseline around 28 weeks gestation
Worksheet Context⧉
Baseline context only
This page is best read as a checklist/reference aid, not as a personalized prediction.
Factors Selected⧉
0
No listed factors selected
Higher-Weight Factors⧉
0
No OR ≥ 2.5 factors selected
Literature Weights Shown⧉
Reference only
Selected odds ratios are shown below as literature-based weights, not as a patient-specific probability model.
Stillbirth Rate by Gestational Age
| Gestational Age | Baseline Rate | Reference Context |
|---|---|---|
| 20 weeks | 3.5 per 1,000 | Earlier gestation baseline |
| 24 weeks | 3.0 per 1,000 | Earlier gestation baseline |
| 28 weeks | 2.8 per 1,000 | Earlier gestation baseline |
| 32 weeks | 2.5 per 1,000 | Earlier gestation baseline |
| 36 weeks | 1.8 per 1,000 | Earlier gestation baseline |
| 37 weeks | 1.5 per 1,000 | Lower late-preterm / early-term baseline |
| 38 weeks | 1.3 per 1,000 | Lower late-preterm / early-term baseline |
| 39 weeks | 1.5 per 1,000 | Lower late-preterm / early-term baseline |
| 40 weeks | 2.0 per 1,000 | Post-term baseline rises again |
| 41 weeks | 3.5 per 1,000 | Post-term baseline rises again |
| 42 weeks | 5.0 per 1,000 | Post-term baseline rises again |
Selected Literature-Based Risk Weights
No risk factors selected. Select risk factors above to see their relative impact.
Planning notes, formulas, and examples
About the Stillbirth Risk Assessment Calculator
Stillbirth — the loss of a baby at 20 or more weeks of pregnancy — is a serious pregnancy outcome, and risk discussion is often easier when the major contributing factors are summarized in one place. This page turns common epidemiologic factors into a worksheet that is easier to discuss than a raw number alone.
The Stillbirth Risk Assessment Calculator combines gestational-age baseline rates with selected relative-risk factors such as maternal age, BMI, medical conditions, and lifestyle exposures. The result is a simplified worksheet output rather than a validated patient-specific stillbirth prediction model.
This calculator is designed as an educational tool to help pregnant individuals understand how selected factors can shift risk context and to support informed conversations with their healthcare providers. It is not a diagnostic tool and should never replace professional medical assessment.
When This Page Helps
Stillbirth risk is easier to discuss when the major influences are separated into gestational age, maternal factors, and modifiable exposures. This calculator keeps those pieces together so the worksheet can support questions for an obstetric visit without turning the result into a single individualized prediction.
How to Use the Inputs
- Enter the current gestational age in weeks.
- Input the maternal age and pre-pregnancy BMI.
- Select all applicable risk factors from the checklist.
- Review the worksheet context compared with the population baseline.
- Use the gestational age table to understand how risk changes over time.
Formula used
This page combines gestational-age baseline rates with literature-based odds ratios for selected factors.
Baseline rates are shown as population reference values by gestational age.
The odds ratios on this page are displayed as educational context only and should not be treated as a validated individualized prediction formula.Example Calculation
Result: Baseline 2.8 per 1,000 at 28 weeks; 2 worksheet factors selected
With a baseline of 2.8 per 1,000 at 28 weeks, age ≥35 and obesity appear as two literature-based worksheet factors. The page uses those relative-risk figures as educational comparison context, not as a validated individualized stillbirth predictor.
Tips & Best Practices
- Use the worksheet to organize questions for your obstetric team rather than to self-manage risk from the number alone.
- Fetal-movement concerns, worsening hypertension, or diabetic-control issues deserve direct clinical review rather than worksheet interpretation.
- A history of stillbirth, fetal growth restriction, or major maternal disease should be discussed directly with the pregnancy care team.
- Lifestyle and chronic-disease management matter, but the page does not quantify how much one change will alter an individual pregnancy outcome.
- Timing decisions in late pregnancy should come from obstetric review, not from the worksheet alone.
Understanding Stillbirth Risk Factors
Stillbirth risk factors fall into two categories: modifiable and non-modifiable. Non-modifiable factors include maternal age over 35, history of previous stillbirth, multiple gestation, and certain chronic medical conditions. Modifiable factors include smoking, obesity, substance use, and inadequate prenatal care.
The strongest evidence-based risk factor is a history of previous stillbirth, which increases the risk approximately 5-fold. That kind of history changes how clinicians frame the pregnancy, but this page does not turn it into an individualized care plan.
Gestational Age and Stillbirth Timing
Stillbirth risk varies significantly across pregnancy. The highest risk periods are before 28 weeks (primarily due to congenital anomalies and preterm placental failure) and after 40+6 weeks (due to post-maturity and placental insufficiency). The lowest risk period is 37-38 weeks.
This U-shaped pattern of risk by gestational age is one reason gestational timing remains an important obstetric topic. The worksheet shows the baseline pattern for context only and does not tell an individual pregnancy when delivery should occur.
Using the Worksheet Responsibly
The output is best used to structure a conversation about baseline risk patterns and selected literature-based factors, not to forecast an individual pregnancy with precision. If the clinical picture is concerning, direct obstetric review matters more than any worksheet number.
Sources & Methodology
Last updated:
Methodology
This worksheet combines gestational-age baseline rates with literature-based relative-risk context to summarize selected stillbirth factors. It is an educational risk-context aid, not a validated individual prediction model.
Sources
- Stillbirth data (CDC) — Population rates and timing context for stillbirth risk.
- Stillbirth (ACOG) — Clinical guidance on risk factors and obstetric context for stillbirth.
Frequently Asked Questions
In the U.S., about 1 in 160 pregnancies (6.2 per 1,000) result in stillbirth after 20 weeks. The rate is highest before 28 weeks and after 41 weeks, with a nadir around 37-38 weeks.
The strongest risk factors are previous stillbirth (OR 5.0), fetal growth restriction (OR 3.9), pre-existing diabetes (OR 2.9), and systemic lupus erythematosus (OR 3.0).
Not every stillbirth is preventable, and this page does not estimate preventability. The practical value of the worksheet is to highlight which factors are present so they can be discussed in context with an obstetric clinician.
Population stillbirth rates rise after 39 weeks, in part because placental reserve may decline as pregnancy continues. The page shows that baseline pattern for context only and does not suggest a management plan from the number alone.
This provides a population-level estimate using published odds ratios. Individual risk depends on many factors not captured here, including placental function, fetal anatomy, and genetic factors.
Decreased fetal movement can be an early warning sign that deserves prompt obstetric review. This page treats fetal-movement awareness as part of the broader pregnancy discussion rather than as a stand-alone prevention guarantee.
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