Women with Diabetes More Likely to Experience Stillbirth
Women with pre-existing diabetes face a 4-5 times higher risk of stillbirth, driven by high blood sugar, BMI, and fetal size issues.
Women with pre-existing diabetes, whether type 1 or type 2, face a significantly elevated risk of stillbirth compared to the general population. Studies show this risk is four to five times higher, with rates of 16.1 per 1000 births for type 1 diabetes and 22.9 per 1000 for type 2, and no substantial improvement over recent years despite declines in the broader obstetric population.
Understanding the Increased Risk
Pregestational diabetes markedly increases stillbirth likelihood, contrasting with falling rates in non-diabetic pregnancies. This disparity highlights the need for targeted interventions. Maternal factors like poor glycemic control and obesity play central roles, with one-third of stillbirths occurring at term, suggesting potential benefits from earlier delivery policies.
Research spanning over 18 years and more than 5,000 infants confirms that high blood sugar levels (measured by HbA1c) and elevated BMI are primary modifiable risk factors. For type 1 diabetes, higher HbA1c across all pregnancy stages correlates with stillbirth, while for type 2, pre-pregnancy levels are particularly predictive.
Key Risk Factors: Blood Sugar and BMI
Maternal hyperglycemia stands out as the most critical modifiable factor. In type 1 diabetes, women experiencing stillbirth had elevated average blood glucose throughout pregnancy. Type 2 diabetes shows a distinct pattern: pre-pregnancy hyperglycemia is a stronger predictor than during-pregnancy levels, underscoring the importance of preconception counseling, which is often underutilized in this group.
High maternal BMI exacerbates risks, especially in type 2 diabetes, where obesity independently contributes via preeclampsia, congenital anomalies, and fetal macrosomia. Efforts to optimize BMI and glucose before conception remain essential.
Fetal Growth Abnormalities and Stillbirth
Infants at the extremes of birthweight face the highest risks. Small for gestational age (SGA, <10th percentile) babies have a sixfold higher stillbirth risk in type 1 diabetes (5 stillbirths vs. 67 live births) and threefold 2 (4 78). large for gestational age (lga,>95th percentile) infants show doubled risk in type 2 diabetes (15 stillbirths vs. 402 live births).
| Fetal Size Category | Type 1 Diabetes Stillbirth Risk | Type 2 Diabetes Stillbirth Risk |
|---|---|---|
| SGA (<10th percentile) | 6x higher | 3x higher |
| 10th-90th percentile (Normal) | Baseline | Baseline |
| LGA (>95th percentile) | Similar to general population | 2x higher |
These patterns mirror general population trends but are amplified in diabetes, with fetal growth restriction as the strongest indicator.
Timing of Stillbirths
Stillbirths occur across gestations but peak late. One-third happen at term: 38th week for type 1 (7.0 per 1000) and 39th week for type 2 (9.3 per 1000). In type 2, stillborn infants deliver over three weeks earlier on average than live births, with 68% preterm versus 24% for live births.
- Preterm stillbirths (<37 weeks): Majority (68% in type 2), requiring better antenatal detection.
- Term stillbirths: Potentially preventable via timing of delivery.
Sex Differences in Stillbirth Risk
A notable finding is the disproportionate male fetal mortality in type 2 diabetes: 81% of stillborns were male versus 50.5% of live births (p=0.0002). Male fetuses are generally 10% more vulnerable, but this study shows fourfold higher rates in type 2 diabetes, warranting further investigation.
Trends Over Time
Stillbirth rates in type 1 diabetes remained stable at 16.1 per 1000 over 18 years. Type 2 saw a minor decline (p=0.02) to 22.9 per 1000, but rates far exceed the general population’s decreasing trend. This stasis emphasizes ongoing challenges in management.
Prevention Strategies
Optimizing glycemic control pre- and during pregnancy is paramount. Preconception counseling for type 2 diabetes patients must improve uptake. High BMI management through lifestyle interventions can mitigate risks. Enhanced fetal monitoring for SGA/LGA infants and consideration of earlier delivery near term may reduce occurrences.
Regular HbA1c monitoring, ultrasound for growth assessment, and multidisciplinary care involving endocrinologists and obstetricians are recommended. Recent research also highlights higher risks in pregestational versus gestational diabetes, with large fetuses in pregestational cases at 21 times the risk of normal-sized fetuses in gestational diabetes.
Comparison: Pregestational vs. Gestational Diabetes
| Diabetes Type | Stillbirth Rate (per 1000) | Key Risks |
|---|---|---|
| Type 1 (Pregestational) | 16.1 | HbA1c all stages, SGA |
| Type 2 (Pregestational) | 22.9 | Pre-pregnancy HbA1c, BMI, LGA, male fetuses |
| Gestational | Lower baseline | Less than pregestational |
Frequently Asked Questions (FAQs)
What is the stillbirth risk for women with diabetes?
4-5 times higher than the general population; 16.1/1000 for type 1 and 22.9/1000 for type 2.
Can blood sugar control prevent stillbirth?
Yes, it’s the key modifiable factor. Lower HbA1c reduces risk significantly.
Why are male fetuses at higher risk in type 2 diabetes?
81% of stillbirths were male vs. 50.5% live births; male vulnerability amplified in this group.
Should delivery be earlier for diabetic pregnancies?
Potentially, as 1/3 stillbirths occur at term; individualized timing advised.
How does fetal size affect risk?
SGA: 3-6x higher; LGA: 2x higher in type 2.
Conclusion
Addressing hyperglycemia, obesity, and fetal growth through preconception care, vigilant monitoring, and timely interventions can substantially lower stillbirth risks for women with diabetes. Ongoing research and policy changes are crucial for progress.
References
- High blood sugar levels and BMI linked to stillbirth in mothers with diabetes — Diabetologia Journal. 2019-07-30. https://diabetologia-journal.org/2019/07/30/high-blood-sugar-levels-and-bmi-linked-to-stillbirth-in-mothers-with-diabetes/
- High Maternal HbA1c, BMI Linked to Stillbirth Risk in Women With Prepregnancy Diabetes — Endocrinology Advisor. Accessed 2026. https://www.endocrinologyadvisor.com/news/adiposity-and-hyperglycemia-may-increase-stillbirth-risk-in-pre-pregnancy-diabetes/
- Factors associated with stillbirth in women with diabetes — PMC (Diabetologia). 2019. https://pmc.ncbi.nlm.nih.gov/articles/PMC6731193/
- New research shows fetal weight at birth impacts delivery for pregnancies with diabetes — Medical University of South Carolina. 2023-11-20. https://www.musc.edu/content-hub/news/2023/11/20/gestational-diabetes-research
- Diabetes, fetal growth and stillbirth — Tommy’s. Accessed 2026. https://www.tommys.org/research/research-topics/stillbirth-research/diabetes-and-risk-stillbirth
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