Seat Belt Use in the US by Pregnant Motor Vehicle Occupants

Corina Espelien; Ruyun Jin; Susan Mostofizadeh; Rachel VanRyzin; Thomas Hartka; Jason Forman; Pavel Chernyavskiy

doi:10.1001/jamanetworkopen.2023.34272

. 2023 Sep 18;6(9):e2334272. doi: 10.1001/jamanetworkopen.2023.34272

Seat Belt Use in the US by Pregnant Motor Vehicle Occupants

Corina Espelien ^1,^✉, Ruyun Jin ², Susan Mostofizadeh ³, Rachel VanRyzin ³, Thomas Hartka ^1,⁴, Jason Forman ¹, Pavel Chernyavskiy ²

¹Department of Mechanical and Aerospace Engineering, Center for Applied Biomechanics, University of Virginia, Charlottesville

²Department of Public Health Sciences, Division of Biostatistics, School of Medicine, University of Virginia, Charlottesville

³Honda Development and Manufacturing of America, LLC, Crash Safety Department, Auto Development Center, Raymond, Ohio

⁴Department of Emergency Medicine, School of Medicine, University of Virginia, Charlottesville

Accepted for Publication: August 10, 2023.

Published: September 18, 2023. doi:10.1001/jamanetworkopen.2023.34272

^✉

Corresponding Author: Corina Espelien, BS, Department of Mechanical and Aerospace Engineering, Center for Applied Biomechanics, University of Virginia, 4040 Lewis and Clark Dr, Charlottesville, VA 22911 (cme2kd@virginia.edu).

Author Contributions: Drs Jin and Chernyavskiy had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Espelien, Mostofizadeh, VanRyzin, Forman, Chernyavskiy.

Acquisition, analysis, or interpretation of data: Espelien, Jin, Mostofizadeh, Hartka, Forman, Chernyavskiy.

Drafting of the manuscript: Espelien, Hartka, Chernyavskiy.

Critical review of the manuscript for important intellectual content: Espelien, Jin, Mostofizadeh, VanRyzin, Forman, Chernyavskiy.

Statistical analysis: Espelien, Jin, Hartka, Chernyavskiy.

Obtained funding: Espelien, Mostofizadeh, VanRyzin, Forman.

Administrative, technical, or material support: Espelien, Mostofizadeh, VanRyzin, Forman.

Supervision: Mostofizadeh, VanRyzin, Forman, Chernyavskiy.

Conflict of Interest Disclosures: Ms Espelien and Drs Jin, Hartka, and Forman reported receiving grants from Honda Motor Co during the conduct of the study. Mss Mostofizadeh and VanRyzin reported being employed by and receiving a salary from Honda Development and Manufacturing of America, LLC. Dr Chernyavskiy reported receiving grants from Honda Motor Co via contract to the Center for Advanced Biomechanics during the conduct of the study and receiving personal fees from Biocore, LLC for statistical consulting unrelated to the current work. No other disclosures were reported.

Funding/Support: Honda Development and Manufacturing of America, LLC provided both technical and financial support to the authors via contract 2000061412.

Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and decision to submit the manuscript for publication. Mss Mostofizadeh and VanRyzin reviewed, edited, and approved the final copy of the submitted manuscript.

Disclaimer: The views expressed in this article are those of the authors and not of the sponsors.

Data Sharing Statement: See Supplement 2.

Additional Contributions: Ms Mary Gallaher, UVA-CAB, provided substantial contributions to the ideation and initialization of this research and was financially compensated as an undergraduate researcher.

^✉

Corresponding author.

PMCID: PMC10507482 PMID: 37721756

Abstract

This cross-sectional study assesses patterns of seat belt use among pregnant, nonpregnant, and male occupants.

Introduction

Motor vehicle (MV) collisions are a leading cause of trauma for pregnant individuals in the US that often result in adverse maternal and fetal outcomes.¹ MV collisions account for 82% of injury-induced fetal deaths and 55% to 78% of trauma-related hospital admissions among pregnant individuals.^1,2 Seat belts are recommended for all occupants, although it remains unclear whether seat belt use differs between pregnant occupants and occupants from other demographic subgroups.³ Using nationally representative survey responses, we assessed patterns of seat belt use among pregnant, nonpregnant, and male occupants.

Methods

This cross-sectional study analyzed responses from the Center of Disease Control and Prevention Behavioral Risk Factor Surveillance System (BRFSS). Use of BRFSS is exempt from institutional review board approval because it is deidentified and publicly available. Data from 2006, 2008, 2010-2018, and 2020 across US states, territories, and the District of Columbia were included to determine prevalence and trends of seat belt use, which was defined as “always wearing a seat belt” in survey responses that are consistent with field observations.⁴ Analysis was compliant with STROBE reporting guidelines. Our exclusion criteria are detailed in the eFigure in Supplement 1. Survey-weighted responses were aggregated by year, age group, sex, and pregnancy status and analyzed using beta regression, with the nonpregnant female group treated as the reference (eMethods in Supplement 1).

Results

A total of 1 389 538 respondents were identified, consisting of 741 032 nonpregnant females (53.3%), 30 193 pregnant females (2.2%), and 618 313 males (44.5%) with unweighted mean (SD) ages 33.3 (7.4), 29.5 (5.8), and 32.3 (7.7) years, respectively. Weighted estimates of seat belt use by year, age, sex, and pregnancy status are shown in the Figure. We found significantly higher seat belt use among respondents aged 30 to 44 years vs those aged 18 to 29 years (odds ratio [OR], 1.62; 95% CI, 1.52-1.72).

Figure. — Weighted sample size was computed based on survey weights in the Behavioral Risk Factor Surveillance System. For the groups aged 18 to 29 years, the weighted sample sizes were 252 million nonpregnant female occupants, 15 million pregnant female occupants, and 289 million male occupants. For the groups aged 30 to 44 years, the weighted sample sizes were 353 million nonpregnant female occupants, 12 million pregnant female occupants, and 360 million male occupants. Data on seat belt use were not available for 2007, 2009, and 2019.

The Table shows age-adjusted estimates of seat belt use for the first (2006) and last (2020) survey year, the annual percent change, and the ORs for comparison with nonpregnant females. In 2020, there was no significant difference between pregnant and nonpregnant female seat belt use at just over 88%, which exceeds the male occupant estimate by 5%. The estimated trend in seat belt use was 0.00%/y (95% CI, −1.65%/y to 1.97%/y) for pregnant females but 3.37%/y (95% CI, 1.77%/y-4.98%/y) for males and 1.96%/y (95% CI, 0.00%/y-3.72%/y) for nonpregnant females.

Table. Age-Adjusted Seat Belt Use Rates by Respondent Sex and Pregnancy Status and Annual Percent Changes of Seat Belt Use Over Time, 2006, 2008, 2010-2018, and 2020^a.

Sex and pregnancy status	Prevalence of respondents “always wearing seat belt,” %				Age-adjusted annual trend in “always wearing seat belt,” mean, %/y
	Survey year 2006		Survey year 2020
	Estimate (95% CI)	OR (95% CI)^b	Estimate (95% CI)	OR (95% CI)^b	Estimate (95% CI)	Difference (95% CI)^b
Nonpregnant female occupants	85.7 (83.9 to 87.4)	1 [Reference]	88.8 (87.3 to 90.1)	1 [Reference]	1.96 (0.00 to 3.72)	1 [Reference]
Pregnant female occupants	88.3 (86.7 to 89.8)	1.26 (1.05 to 1.51)	88.5 (87.0 to 89.9)	0.98 (0.82 to 1.17)	0.00 (−1.65 to 1.97)	−1.80 (−4.03 to 0.00)
Male occupants	75.8 (73.3 to 78.2)	0.52 (0.44 to 0.62)	83.4 (81.6 to 85.1)	0.64 (0.54 to 0.75)	3.37 (1.77 to 4.98)	1.42 (0.00 to 3.43)

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Abbreviation: OR, odds ratio.

^{^a}

Data on seat belt use were not available for 2007, 2009, and 2019. Data are from the Behavioral Risk Factor Surveillance System.

^{^b}

Adjustments for multiple comparisons were made via the Dunnett method, treating nonpregnant female occupants as the control group.

Discussion

We used nationally representative survey data to examine patterns of seat belt use among pregnant female occupants, a group with a wide range of previously reported US-based rates (76%-94%).³ We found that seat belt use among pregnant and nonpregnant occupants was similarly high during the most recent survey year. Unlike nonpregnant female occupants and male occupants, whose seat belt use increased over time, pregnant occupants showed flat trends, indicating a potential barrier to habitual use. Prior estimates of pregnant occupant seat belt use have often been derived from convenience samples, which can be limited in sample size or biased due to involvement in a MV collision, trauma admission, or the setting of data collection.⁵ To our knowledge, our study provides the first national estimate of seat belt use among pregnant occupants that minimizes selection bias; however, like any survey, BRFSS is limited by the self-reported nature of the data.

Among pregnant occupants, common reasons for not wearing a seat belt include forgetting, abdominal discomfort,³ and perceived uncertainty about its effect on maternal and fetal safety.⁶ Standard reminder systems can mitigate forgetfulness, but changes to belt system design may also improve habitual use by alleviating discomfort and accommodating the unique needs of pregnant occupants. Additionally, increasing awareness around the sustained benefits of seat belts throughout pregnancy may reduce the rate and severity of maternal and fetal collision-related injuries, especially among younger occupants whose seat belt use rates are lower than those of older occupants. These discussions can be initiated by obstetrics professionals during routine prenatal visits, in line with American College of Obstetricians and Gynecologists guidance recommending pregnant individuals always wear a seat belt.

Supplement 1.

eFigure. Exclusion Criteria Related to Seat Belt Use Analysis, With Unweighted Number of Observations Excluded and Remaining in Dataset, BRFSS, 2006, 2008, 2010-2018, 2020 (Belt Use Data Not Available for 2007, 2009, 2019)

eMethods.

eReferences.

Click here for additional data file.^{(268.2KB, pdf)}

Supplement 2.

Data Sharing Statement

Click here for additional data file.^{(16.7KB, pdf)}

References

1.Oxford CM, Ludmir J. Trauma in pregnancy. Clin Obstet Gynecol. 2009;52(4):611-629. doi: 10.1097/GRF.0b013e3181c11edf [DOI] [PubMed] [Google Scholar]
2.Weiss HB, Songer TJ, Fabio A. Fetal deaths related to maternal injury. JAMA. 2001;286(15):1863-1868. doi: 10.1001/jama.286.15.1863 [DOI] [PubMed] [Google Scholar]
3.McGwin G Jr, Russell SR, Rux RL, Leath CA, Valent F, Rue LW. Knowledge, beliefs, and practices concerning seat belt use during pregnancy. J Trauma. 2004;56(3):670-675. doi: 10.1097/01.TA.0000117014.57431.1D [DOI] [PubMed] [Google Scholar]
4.Shakya I, Shults RA, Stevens MR, Beck LF, Sleet DA. State-level seat belt use in the United States, 2011-2016: comparison of self-reported with observed use and use by fatally injured occupants. J Safety Res. 2020;73:103-109. doi: 10.1016/j.jsr.2020.02.015 [DOI] [PMC free article] [PubMed] [Google Scholar]
5.Sartin EB, Lombardi LR, Metzger KB, Myers RK, Pfeiffer MR, Curry AE. Variation in drivers’ seat belt use by indicators of community-level vulnerability. J Safety Res. 2023;85:140-146. doi: 10.1016/j.jsr.2023.01.013 [DOI] [PMC free article] [PubMed] [Google Scholar]
6.Taylor AJ, McGwin G Jr, Sharp CE, et al. Seatbelt use during pregnancy: a comparison of women in two prenatal care settings. Matern Child Health J. 2005;9(2):173-179. doi: 10.1007/s10995-005-4906-2 [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplement 1.

eMethods.

eReferences.

Click here for additional data file.^{(268.2KB, pdf)}

Supplement 2.

Data Sharing Statement

Click here for additional data file.^{(16.7KB, pdf)}

[zld230179r1] 1.Oxford CM, Ludmir J. Trauma in pregnancy. Clin Obstet Gynecol. 2009;52(4):611-629. doi: 10.1097/GRF.0b013e3181c11edf [DOI] [PubMed] [Google Scholar]

[zld230179r2] 2.Weiss HB, Songer TJ, Fabio A. Fetal deaths related to maternal injury. JAMA. 2001;286(15):1863-1868. doi: 10.1001/jama.286.15.1863 [DOI] [PubMed] [Google Scholar]

[zld230179r3] 3.McGwin G Jr, Russell SR, Rux RL, Leath CA, Valent F, Rue LW. Knowledge, beliefs, and practices concerning seat belt use during pregnancy. J Trauma. 2004;56(3):670-675. doi: 10.1097/01.TA.0000117014.57431.1D [DOI] [PubMed] [Google Scholar]

[zld230179r4] 4.Shakya I, Shults RA, Stevens MR, Beck LF, Sleet DA. State-level seat belt use in the United States, 2011-2016: comparison of self-reported with observed use and use by fatally injured occupants. J Safety Res. 2020;73:103-109. doi: 10.1016/j.jsr.2020.02.015 [DOI] [PMC free article] [PubMed] [Google Scholar]

[zld230179r5] 5.Sartin EB, Lombardi LR, Metzger KB, Myers RK, Pfeiffer MR, Curry AE. Variation in drivers’ seat belt use by indicators of community-level vulnerability. J Safety Res. 2023;85:140-146. doi: 10.1016/j.jsr.2023.01.013 [DOI] [PMC free article] [PubMed] [Google Scholar]

[zld230179r6] 6.Taylor AJ, McGwin G Jr, Sharp CE, et al. Seatbelt use during pregnancy: a comparison of women in two prenatal care settings. Matern Child Health J. 2005;9(2):173-179. doi: 10.1007/s10995-005-4906-2 [DOI] [PubMed] [Google Scholar]

PERMALINK

Seat Belt Use in the US by Pregnant Motor Vehicle Occupants

Corina Espelien, BS

Ruyun Jin, MD, MCR

Susan Mostofizadeh, BSE

Rachel VanRyzin, BSE

Thomas Hartka, MD, MS

Jason Forman, PhD

Pavel Chernyavskiy, PhD

Abstract

Introduction

Methods

Results

Figure. Prevalence of Occupants “Always Wearing a Seat Belt” When Driving or Riding in a Car by Year, Age Group, Sex, and Pregnancy Status in the US, 2006, 2008, 2010-2018, and 2020.

Table. Age-Adjusted Seat Belt Use Rates by Respondent Sex and Pregnancy Status and Annual Percent Changes of Seat Belt Use Over Time, 2006, 2008, 2010-2018, and 2020^a.

Discussion

References

Associated Data

Supplementary Materials

ACTIONS

PERMALINK

RESOURCES

Cite

Add to Collections

PERMALINK

Seat Belt Use in the US by Pregnant Motor Vehicle Occupants

Corina Espelien, BS

Ruyun Jin, MD, MCR

Susan Mostofizadeh, BSE

Rachel VanRyzin, BSE

Thomas Hartka, MD, MS

Jason Forman, PhD

Pavel Chernyavskiy, PhD

Abstract

Introduction

Methods

Results

Figure. Prevalence of Occupants “Always Wearing a Seat Belt” When Driving or Riding in a Car by Year, Age Group, Sex, and Pregnancy Status in the US, 2006, 2008, 2010-2018, and 2020.

Table. Age-Adjusted Seat Belt Use Rates by Respondent Sex and Pregnancy Status and Annual Percent Changes of Seat Belt Use Over Time, 2006, 2008, 2010-2018, and 2020a.

Discussion

References

Associated Data

Supplementary Materials

ACTIONS

PERMALINK

RESOURCES

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Table. Age-Adjusted Seat Belt Use Rates by Respondent Sex and Pregnancy Status and Annual Percent Changes of Seat Belt Use Over Time, 2006, 2008, 2010-2018, and 2020^a.