Key points
- The incidence of stillbirth in the U.S. is more significant than earlier reports indicated, with about 1 in 150 births resulting in stillbirth. This figure rises to 1 in 112 in low-income regions.
- While over 70% of stillbirths happened in pregnancies with at least one recognized clinical risk factor (like chronic hypertension), a considerable number—particularly for those at 40 weeks gestation or beyond—had no such factors.
- Researchers argue that these findings underscore the necessity for enhanced prevention methods for stillbirths in at-risk pregnancies, along with improved risk prediction, especially as pregnancies progress.
A recent study by researchers at Harvard T.H. Chan School of Public Health and Mass General Brigham reveals that stillbirths occur at a higher rate in the U.S. than previously acknowledged.
The study found that although most stillbirths were linked to at least one clinical risk factor, a significant number had none, especially among those occurring after 40 weeks of gestation.
“Stillbirths affect nearly 21,000 families annually in the U.S., and it’s estimated that nearly half of those that happen at or after 37 weeks could be prevented. However, research in this area is quite limited,” remarked co-senior author Jessica Cohen, PhD, a health economics professor. “This study highlights an urgent need to bolster stillbirth risk prediction and preventive strategies.”
This research will appear in the upcoming issue of JAMA on October 27, 2025. The researchers indicate it’s one of the most extensive studies on stillbirth burden so far.
Analyzing over 2.7 million pregnancies in the U.S. from 2016 to 2022, the researchers utilized commercial health insurance claims and demographic data from various sources. Among these pregnancies, there were 18,893 cases of stillbirth. The team assessed associations with various clinical factors—like gestational age at delivery, pregnancy and fetal risk factors, and obstetric complications—while also looking into socioeconomic influences such as income and access to obstetric care.
The study identified that more than 1 in 150 births ends in stillbirth, surpassing the CDC’s estimate of 1 in 175 as the national average. In low-income areas, the rate was even higher, with 1 in 112 births resulting in stillbirth. Moreover, areas with a greater proportion of Black families reported rates of 1 in 95. Interestingly, stillbirth rates did not substantially differ based on rurality or access to care.
Furthermore, the study indicated that while 72.3% of stillbirths had at least one clinical risk factor, a notable 27.7% occurred without any identified risk factor. Particularly, later gestational ages displayed higher rates of absent clinical risks: 24.1% at 38 weeks, 34.2% at 39 weeks, and 40.7% at 40 weeks or more. Rates tended to be elevated in pregnancies with low amniotic fluid levels, chronic hypertension, and fetal anomalies.
“Despite recent efforts to enhance stillbirth research and prevention, rates in the U.S. remain alarmingly higher than in comparable countries,” noted co-senior author Mark Clapp, MD, MPH, from the Department of Obstetrics and Gynecology at Massachusetts General Hospital. “It’s my hope that our findings will guide changes in policy and practice, ensuring that no family has to endure such a loss.”
The researchers emphasized the need for additional inquiries into the socioeconomic factors influencing stillbirth rate disparities—be it social determinants, health system barriers, or clinical risk factors.
Haley Sullivan, a doctoral student in the Harvard PhD Program in Health Policy, served as the lead author, with co-authorship by Anna Sinaiko from Harvard Chan.
