What is Stillbirth?
Stillbirth is defined as the death of a fetus at or after 20 weeks of gestation (in the US; 24 weeks in the UK and some other countries). It is one of the most devastating pregnancy outcomes, affecting approximately 1 in 175 pregnancies in the United States, which translates to roughly 21,000 stillbirths per year.
The overall US stillbirth rate is approximately 5.7 per 1,000 total births, though this includes both early (20–27 weeks) and late (≥28 weeks) stillbirths. The late stillbirth rate, which is more commonly used in international comparisons, is about 3.1 per 1,000 births. Globally, there are an estimated 2 million stillbirths per year, with the vast majority occurring in low- and middle-income countries.
While many stillbirths remain unexplained even after thorough investigation, a substantial proportion are associated with identifiable risk factors that may be modifiable through prenatal care and lifestyle changes.
Risk Factors
| Risk Factor | Relative Risk (RR) | Modifiable? | Notes |
|---|---|---|---|
| Maternal age 35–39 | 1.5 | No | Risk increases progressively after 35 |
| Maternal age ≥40 | 2.0 | No | Strongest age-related risk |
| Obesity (BMI ≥30) | 2.0 | Yes (pre-pregnancy) | Weight management before pregnancy helps |
| Smoking during pregnancy | 1.5 | Yes | Quitting at any point reduces risk |
| Previous stillbirth | 2.5 | No | Enhanced surveillance recommended |
| Pre-existing diabetes | 2.5 | Partially | Tight glucose control reduces risk |
| Pre-existing hypertension | 2.0 | Partially | Blood pressure management is key |
| Multiple pregnancy | 3.0 | No | Twins/triplets require close monitoring |
| Placental problems | 3.0–5.0 | No | Major cause of stillbirth |
How Risk is Calculated
This calculator uses a multiplicative risk model based on published relative risk data:
Where the baseline rate is 3.1 per 1,000 births (US late stillbirth rate) and each RR (relative risk) represents the increased probability associated with each applicable risk factor. For example, a 38-year-old (RR 1.5) with obesity (RR 2.0) who smokes (RR 1.5) would have:
It is important to note that this multiplicative model is a simplification. Risk factors may interact in complex ways, and the actual risk for any individual may differ from this estimate. This tool is intended to illustrate the cumulative impact of risk factors, not to provide a precise clinical prediction.
Prevention Strategies
While not all stillbirths are preventable, evidence-based strategies can significantly reduce risk:
- Regular prenatal care: Attending all scheduled appointments allows for monitoring of fetal growth and well-being
- Fetal movement monitoring: Being aware of your baby's movement patterns and reporting any changes
- Smoking cessation: Quitting smoking at any stage of pregnancy reduces stillbirth risk
- Sleep position: Research suggests that sleeping on your side (particularly left side) after 28 weeks may reduce risk compared to sleeping on your back
- Managing chronic conditions: Tight blood glucose control for diabetes and blood pressure management for hypertension
- Healthy weight: Achieving a healthy BMI before conception
- Avoiding alcohol and drugs: Both increase stillbirth risk
- Timely delivery: For high-risk pregnancies, planned delivery at 37–39 weeks may be recommended
Fetal Kick Counting
Fetal kick counting is one of the most accessible tools for monitoring fetal well-being. While methods vary, a common approach is the "count to 10" method:
- Choose a time when your baby is usually active (often after meals or in the evening)
- Sit comfortably or lie on your side
- Time how long it takes to feel 10 distinct movements (kicks, rolls, flutters)
- Most babies will make 10 movements within 1–2 hours
- Do this at roughly the same time each day to establish a baseline
You should contact your healthcare provider if you notice: fewer movements than usual, a significant change in the pattern of movement, fewer than 10 movements in 2 hours, or no movement at all. Do not wait until the next day to report reduced movements.
When to Seek Care
Contact your healthcare provider immediately if you experience any of the following:
- Decreased or absent fetal movements
- Vaginal bleeding in the second or third trimester
- Severe abdominal pain or cramping
- Sudden severe swelling of face, hands, or feet
- Severe headache with vision changes
- Leaking fluid from the vagina
- Fever above 38 degrees Celsius (100.4 degrees Fahrenheit)
If you cannot reach your provider, go to your nearest emergency department. It is always better to be evaluated and reassured than to delay seeking care when something feels wrong.
Modifying Your Risk
Before Pregnancy
- Achieve a healthy weight (BMI 18.5–24.9)
- Quit smoking and avoid secondhand smoke
- Optimize management of diabetes, hypertension, and other chronic conditions
- Begin taking folic acid supplements
- Discuss previous pregnancy losses with your healthcare provider
During Pregnancy
- Attend all prenatal appointments
- Monitor fetal movements daily from 28 weeks
- Sleep on your side after 28 weeks
- Maintain good blood glucose control if diabetic (HbA1c < 6.5%)
- Take low-dose aspirin if recommended by your provider for preeclampsia prevention
- Avoid alcohol, recreational drugs, and unnecessary medications
- Report any concerning symptoms immediately
Frequently Asked Questions
How accurate is this calculator?
This calculator provides a rough educational estimate based on population-level relative risk data. It is not a validated clinical prediction tool. The multiplicative risk model is a simplification that does not account for interactions between risk factors, protective factors, or individual variation. Always discuss your personal risk with your healthcare provider.
What causes stillbirth?
The most common identified causes include placental problems (abruption, insufficiency), birth defects and genetic abnormalities, fetal growth restriction, infections, umbilical cord problems, and maternal medical conditions. In approximately 25–60% of cases (depending on the thoroughness of investigation), no definitive cause is identified.
Does a previous stillbirth increase risk in future pregnancies?
Yes. Women who have experienced a previous stillbirth have approximately 2–3 times the risk in subsequent pregnancies. However, the majority of women who have had a stillbirth go on to have a healthy baby in their next pregnancy. Enhanced surveillance, including more frequent ultrasounds and fetal monitoring, is typically recommended.
Can stress cause stillbirth?
While severe psychological stress has been associated with adverse pregnancy outcomes in some studies, the relationship is complex and not fully understood. Chronic stress may contribute to behaviors (smoking, poor nutrition) and physiological changes (elevated cortisol, inflammation) that increase risk. Managing stress through healthy coping mechanisms is beneficial for overall pregnancy health.
What happens after a stillbirth?
After a stillbirth, parents are typically offered an autopsy and placental examination to try to determine the cause. Bereavement support and counseling should be offered. In future pregnancies, closer monitoring is recommended. Organizations like the Stillbirth Foundation and March of Dimes provide resources and support for families affected by stillbirth.