Nonoccupational Physical Activity During Pregnancy,Behavioral Risk Factor Surveillance System,United States,2023

Abstract

Physical activity during pregnancy has numerous health benefits. This cross-sectional study examined the prevalence of nonoccupational physical activity among pregnant women aged 18 to 49 years in the United States. Using 2023 Behavioral Risk Factor Surveillance System data, we estimated the prevalence of meeting the aerobic guideline (≥150 minutes/week of moderate intensity–equivalent aerobic activity) and muscle-strengthening activity (≥2 episodes/week) among 2104 pregnant women aged 18 to 49 years in the United States and explored sociodemographic differences with adjusted logistic regression modeling. Overall, 49.0% (44.5%-53.4%) and 28.6% (24.9%-32.2%) of women met the aerobic activity guideline and participated in ≥2 episodes per week of muscle-strengthening activity, respectively. In adjusted analyses, we found sociodemographic differences for meeting the aerobic activity guideline (by age, race and ethnicity, and general health) and for participating in ≥2 episodes per week of muscle-strengthening activity (by general health). Opportunities exist to increase physical activity among pregnant women of diverse backgrounds through comprehensive, multilevel approaches so that more people can experience its health benefits.

Keywords

physical activity pregnancy epidemiology public health surveillance

Physical activity has numerous health benefits during pregnancy and can prevent or mitigate disease.¹ For example, physical activity during pregnancy can reduce symptoms of postpartum depression and the risk for gestational diabetes.^1,2 Additionally, it can reduce the risk of excessive weight gain during pregnancy, which, in turn, mitigates the risk of developing future obesity, having an infant with high birth weight, or retaining excessive weight after pregnancy.^1,2 Furthermore, physical activity can lower the risk for preeclampsia, reduce the duration of labor, or decrease the risk for Cesarean section.¹ The 2018 Physical Activity Guidelines recommend that pregnant women participate in ≥150 minutes per week of moderate-intensity aerobic physical activity and can continue habitual pre-pregnancy, vigorous-intensity aerobic physical activity.¹ The American College of Obstetricians and Gynecologists recommends that women with uncomplicated pregnancies engage in aerobic and muscle-strengthening physical activity.³

Recent estimates for participation in physical activity during pregnancy are limited.^4-6 It is unclear whether some sociodemographic groups have different levels of participation in physical activity during pregnancy, thus not fully experiencing its associated health benefits. It is important to understand the current prevalence of physical activity during pregnancy to inform public health and clinical practice. This information can help identify groups that may benefit from focused approaches at the levels of society, community, organization, and interpersonal support to promote physical activity.⁷ This study examined the prevalence of nonoccupational aerobic and muscle-strengthening activity among pregnant women aged 18 to 49 years in the United States, overall and by sociodemographic characteristics.

Methods

For this cross-sectional study, we used 2023 data from the Behavioral Risk Factor Surveillance System (BRFSS), a state-based, telephone health survey representative of noninstitutionalized adults residing in the United States (median response rate: 44.7%).^8,9 From 76 642 participants identifying as women aged 18 to 49 years, we excluded 74 518 who did not report a current pregnancy and 20 participants who were missing data on both nonoccupational aerobic activity and muscle-strengthening activity, resulting in an analytic sample of 2104 pregnant women.

If participants reported any past-month nonoccupational aerobic activity, they then described the types and duration of their 2 most common activities (without specifying intensity). From these responses, we calculated minutes per week of moderate intensity–equivalent aerobic activity (ie, we doubled each minute of vigorous-intensity activity, consistent with literature on meeting the general adult aerobic guideline).^10-12 Participants then reported past-month frequency of muscle-strengthening activity. Details of measurement are available in survey documentation.¹³ We created 2 primary outcome variables: (1) meeting the aerobic guideline with ≥150 minutes per week of moderate intensity–equivalent aerobic activity and (2) participating in ≥2 episodes per week of muscle-strengthening activity, corresponding to the general adult guideline for muscle-strengthening activity. A secondary outcome was participation in any muscle-strengthening activity in the past month based on distribution of data (weighted median [IQR] of 0 [0-2] episodes per week).

We compared the prevalence of the primary outcomes between the analytic sample and 71 481 nonpregnant women aged 18 to 49 years not missing data on both aerobic and muscle-strengthening activity (hereinafter, nonpregnant counterparts) by using the Wald χ² test. Additionally, we described the most common physical activities among the analytic sample and their nonpregnant counterparts.

We conducted the remaining analyses in the analytic sample. We conducted the Wald χ² test to identify differences by sociodemographic characteristics for outcomes and considered P < .05 to be significant. Then, we created a logistic regression model for each outcome, adjusting for age, race and ethnicity, education, employment, general health, and number of children in the household and defined significance as 95% CIs for the adjusted prevalence odds ratios (APORs) excluding 1. We calculated minutes per week of aerobic activity.

We did not report some estimates in accordance with Behavioral Risk Factor Surveillance System guidance.¹⁴ We conducted our analysis using RStudio (version 2024.09.0+375, Posit) in 2024, applying survey weights with the “survey” package. All results were weighted unless otherwise stated. Because we used deidentified data from publicly available sources, the Centers for Disease Control and Prevention Institutional Review Board considered this study exempt, and informed consent was not required. We conducted the study according to applicable federal law and Centers for Disease Control and Prevention policy.

Results

Pregnant women in the sample were primarily aged 25 to 34 years, were non-Hispanic White, attended or graduated from college or technical school, and were employed for wages or self-employed (Table 1). In weighted analyses, we found no sociodemographic differences between the analytic sample and 20 excluded pregnant women who were missing data on both aerobic and muscle-strengthening activity.

Table 1.

Weighted unadjusted prevalence and adjusted prevalence odds ratios of nonoccupational aerobic activity (≥150 minutes per week) and muscle-strengthening activity (≥2 episodes per week), by sociodemographic characteristics, among pregnant women aged 18 to 49 years, Behavioral Risk Factor Surveillance System, 2023^a

Characteristic	≥150 Minutes per week of moderate intensity–equivalent aerobic activity				≥2 Episodes per week of muscle-strengthening activity
Characteristic	Unweighted no.^b	Unadjusted % (95% CI)	P value^c	APOR (95% CI)^d	Unweighted no.^b	Unadjusted % (95% CI)	P value^c	APOR (95% CI)^d
Overall	1751	49.0 (44.5-53.4)	—	—	2064	28.6(24.9-32.2)	—	—
Age, y			.22				.79
18-24	327	46.4(37.0-55.8)		1 [Reference]	375	29.8(21.6-38.1)		1 [Reference]
25-29	439	47.0(38.0-56.1)		0.99 (0.56-1.74)	527	28.9 (22.2-35.5)		0.94 (0.56-1.58)
30-34	493	47.2 (38.9-55.4)		0.98 (0.55-1.72)	581	25.1 (18.9-31.3)		0.72 (0.43-1.21)
35-39	318	48.8 (39.4-58.3)		1.05 (0.57-1.93)	383	30.6 (22.6-38.6)		1.00 (0.56-1.78)
40-49	174	68.6 (54.4-82.7)		2.47 (1.16-5.27)	198	32.0 (16.6-47.4)		1.05 (0.50-2.24)
Race and ethnicity			.001				.09
Non-Hispanic American Indian or Alaska Native	37	—^e		—^e	42	—^e		—^e
Non-Hispanic Asian	87	46.0 (29.7-62.3)		0.46 (0.20-1.03)	102	38.9 (23.5-54.2)		1.12 (0.54-2.32)
Non-Hispanic Black	152	45.4 (31.6-59.2)		0.58 (0.32-1.07)	173	25.7 (15.8-35.6)		0.74 (0.40-1.34)
Hispanic	441	37.4 (28.6-46.2)		0.46 (0.28-0.74)	527	23.8 (16.8-30.8)		0.76 (0.47-1.21)
Non-Hispanic multiracial	79	40.4 (22.0-58.7)		0.56 (0.24-1.28)	86	21.9 (10.0-33.9)		0.75 (0.35-1.60)
Non-Hispanic Native Hawaiian or Other Pacific Islander	17	—^e		—^e	20	—^e		—^e
Non-Hispanic another single race	10	—^e		—^e	15	—^e		—^e
Non-Hispanic White	907	60.1 (53.9-66.3)		1 [Reference]	1073	33.2 (27.8-38.6)		1 [Reference]
Education			.02				.17
Graduated from college or technical school	745	57.1 (50.5-63.7)		1 [Reference]	881	32.6 (27.3-37.9)		1 [Reference]
Attended college or technical school	409	51.1 (42.5-59.8)		0.83 (0.52-1.32)	494	29.6 (22.1-37.2)		0.98 (0.63-1.53)
High school graduate or lower education	589	42.5 (35.0-49.9)		0.82 (0.51-1.34)	679	25.0 (19.2-30.9)		0.95 (0.60-1.51)
Employment			.18				.04
Employed for wages or self-employed	1086	51.1 (45.3-56.8)		1 [Reference]	1282	30.7 (26.0-35.3)		1 [Reference]
Homemaker	304	45.9 (36.0-55.7)		0.98 (0.58-1.63)	365	24.3 (15.6-32.9)		0.71 (0.40-1.26)
Out of work, unable to work, or retired	264	40.4 (28.7-52.1)		0.89 (0.50-1.57)	313	20.6 (13.9-27.3)		0.65 (0.38-1.11)
Student	77	64.0 (45.7-82.2)		2.40 (0.87-6.64)	83	47.7 (27.6-67.7)		2.05 (0.79-5.30)
General health			.004				.002
Excellent	382	58.4 (49.4-67.4)		1 [Reference]	444	39.5 (30.8-48.1)		1 [Reference]
Very good	637	53.4 (45.7-61.1)		0.77 (0.47-1.24)	757	29.5 (23.5-35.5)		0.58 (0.37-0.91)
Good, fair, or poor	728	40.5 (33.9-47.1)		0.54 (0.33-0.87)	859	21.8 (16.8-26.8)		0.40 (0.26-0.61)
No. of children in the household			.53				.32
0	665	48.8 (41.9-55.7)		1 [Reference]	778	31.7 (25.3-38.0)		1 [Reference]
1	487	52.7 (43.7-61.7)		1.33 (0.82-2.15)	583	24.9 (19.0-30.8)		0.72 (0.45-1.13)
≥2	594	46.0 (38.4-53.5)		1.03 (0.65-1.63)	695	27.9 (21.7-34.0)		0.92 (0.59-1.45)

Abbreviation: —, does not apply; APOR, adjusted prevalence odds ratio.

Data source: Centers for Disease Control and Prevention.⁹

Participants were not included in unadjusted analyses for a characteristic if they were missing data for that characteristic.

Using the Wald χ² test to identify differences by sociodemographic characteristics for each outcome in unadjusted analyses.

Derived from logistic regression models adjusting for age, race and ethnicity, education, employment, general health, and number of children in the household. Observations with missing covariate data were not included, resulting in 1695 and 1998 observations used for models for aerobic and muscle-strengthening activity, respectively. The racial and ethnic groups non-Hispanic American Indian or Alaska Native, non-Hispanic Native Hawaiian or other Pacific Islander, and non-Hispanic another single race are included in modeling, but estimates for those groups are not reported in accordance with Behavioral Risk Factor Surveillance System guidance.

Estimate not reported in accordance with Behavioral Risk Factor Surveillance System guidance.¹⁴

Overall, 49.0% (95% CI, 44.5%-53.4%) of pregnant women met the aerobic guideline, with differences by race and ethnicity, education, and general health, and 28.6% (95% CI, 24.9% to 32.2%) participated in ≥2 episodes per week of muscle-strengthening activity, with differences by employment and general health (Table 1). These prevalence estimates were lower than the 58.3% (95% CI, 57.5%-59.1%) (denominator = 61 289) and 38.0% (95% CI, 37.3%-38.7%) (denominator = 70 226) of their nonpregnant counterparts who met the aerobic guideline and participated in ≥2 episodes per week of muscle-strengthening activity, respectively (P < .001 for both). Nearly half (49.7%) of pregnant women and more than half (52.5%) of their nonpregnant counterparts reported walking, and all other activities (eg, running or jogging, weight lifting) were reported by <17% and <22% of pregnant women and their nonpregnant counterparts, respectively (Table 2).

Table 2.

Most common nonoccupational physical activities among pregnant and nonpregnant women aged 18 to 49 years, Behavioral Risk Factor Surveillance System, United States, 2023^a,b,c

Activity	Pregnant (n = 1751)		Nonpregnant (n = 61 289)
Activity	Unweighted no.	Weighted % (95% CI)	Unweighted no.	Weighted % (95% CI)
Walking	947	49.7 (45.2-54.1)	33 475	52.5 (51.7-53.3)
Other	308	16.3 (13.0-19.7)	13 822	21.6 (21.0-22.3)
Running or jogging	146	9.6 (7.0-12.3)	7913	13.9 (13.3-14.5)
Weight lifting	151	8.8 (6.2-11.4)	7756	12.4 (11.9-13.0)
Household activities	113	6.3 (4.4-8.1)	3626	5.7 (5.3-6.0)
Yoga, Pilates, or Tai Chi	114	4.6 (3.3-5.9)	4396	7.0 (6.5-7.4)
Gardening or yardwork	122	4.5 (3.2-5.9)	5236	7.0 (6.6-7.4)
Bicycling or bicycling machine	57	2.2 (1.3-3.1)	3827	5.7 (5.3-6.1)
Aerobics video or class	38	—^c	1855	2.7 (2.4-3.0)
Elliptical/EFX machine	22	—^c	1130	1.8 (1.6-2.0)
Calisthenics	17	—^c	1044	1.5 (1.4-1.7)

Data source: Centers for Disease Control and Prevention.⁹

Women aged 18 to 49 years were included if they had complete data on aerobic activity.

If participants reported any past-month, nonoccupational physical activity, they then described the type of their 2 most common activities.

Estimate not reported in accordance with Behavioral Risk Factor Surveillance System guidance.¹⁴

In adjusted analyses for meeting the aerobic guideline for pregnant women, women aged 40 to 49 years were more likely than women aged 18 to 24 years (APOR = 2.47 [95% CI, 1.16-5.27]); Hispanic women were less likely than non-Hispanic White women (APOR = 0.46 [95% CI, 0.28-0.74]); and women with good, fair, or poor general health were less likely than women with excellent general health (APOR = 0.54 [95% CI, 0.33-0.87]) to meet the aerobic guideline (Table 1). In adjusted analyses for ≥2 episodes per week of muscle-strengthening activity for pregnant women, women with very good or good, fair, or poor general health were less likely than women with excellent general health (APOR = 0.58 [95% CI, 0.37-0.91] and 0.40 [95% CI, 0.26-0.61], respectively) to meet this outcome.

Overall, pregnant women participated in a median (IQR) of 135 (0-350) and 100 (0-300) minutes per week of moderate intensity–equivalent aerobic activity and only moderate-intensity aerobic activity, respectively (Supplemental Table 1). Among those with any vigorous-intensity aerobic activity, pregnant women participated in a median (IQR) of 100 (45-210) minutes per week of only vigorous-intensity aerobic activity. Overall, 43.2% (95% CI, 39.1%-47.3%) of pregnant women participated in any muscle-strengthening activity, with differences by race and ethnicity, employment, and general health in adjusted analyses (Supplemental Table 2).

Discussion

In 2023, pregnant women in the United States were less active than their nonpregnant counterparts; half of pregnant women met the aerobic guideline and more than one-quarter of pregnant women participated in ≥2 episodes per week of muscle-strengthening activity. In adjusted analyses, we found differences for meeting the aerobic guideline (by age, race and ethnicity, and general health) and for participating in ≥2 episodes per week of muscle-strengthening activity (by general health) among pregnant women. Thus, opportunities exist to promote physical activity during pregnancy so that more women can experience its numerous health benefits in this unique life stage.

Our findings provide updated data on the prevalence of physical activity during pregnancy, which differs by some characteristics. A study using BRFSS data from 2011, 2013, 2015, and 2017 indicated that 39% of pregnant women participated in ≥150 minutes per week of moderate-intensity aerobic physical activity and 70% did not participate in muscle-strengthening activity.⁴ However, our findings are not directly comparable because of fluctuations in prevalence estimates of physical activity, possibly attributable to different BRFSS question ordering and nonresponse.¹³ Another study that used 1999-2006 data identified differences in moderate and vigorous activity during pregnancy by gestational age, race and ethnicity, and health insurance coverage.¹⁵ Our study aligns with a previous review finding that aerobic physical activity is associated with older age and differs by ethnicity; however, our adjusted analyses do not correspond with that review’s finding that higher education is associated with more physical activity.¹⁶ That review also identified mixed evidence about the relationships between physical activity during pregnancy, work, and having children.¹⁶

Our findings emphasize the importance of opportunities to increase physical activity among pregnant women of diverse backgrounds. Approaches at the levels of society (eg, activity-friendly zoning), community (eg, improved infrastructure for physical activity, especially for walking), organization (eg, training to prepare professionals to support pregnant women’s physical activity), and interpersonal (eg, child care support to allow more time for pregnant women to exercise) support can work together to help pregnant women increase their physical activity, especially women with low levels of participation in physical activity.¹⁶ Additionally, obstetric care clinicians have critical roles in recommending safe physical activity for pregnant women without medical contraindications.^3,16 For all approaches, it is important to seek community input about addressing barriers to physical activity during pregnancy.^17,18

This study had several limitations. First, this study included self-reported pregnancy status without laboratory confirmation or additional pre-pregnancy or pregnancy information (eg, parity, pre-pregnancy body mass index, gestational age, physical activity contraindications). Second, this study relied on self-reported physical activity measures, which are potentially subject to recall and social desirability biases,¹⁹ and did not consider the role of occupational physical activity. Third, participants could only report 2 activities, potentially underestimating levels of physical activity.²⁰ Fourth, calculations for minutes per week of moderate intensity–equivalent aerobic activity were based on intensity values that are nonspecific to pregnancy,¹⁰ potentially under- or over-estimating meeting the aerobic guideline among pregnant women.²¹ Fifth, small sample sizes prevented the presentation of prevalence estimates for some racial and ethnic groups (eg, non-Hispanic American Indian or Alaska Native) and exploring differences between those groups and other racial and ethnic groups.

Overall, we used a large sample from a state-based survey to estimate levels of physical activity during pregnancy. Comprehensive multilevel approaches can promote physical activity among pregnant women of diverse backgrounds to better align with national and clinical guidelines so that more people can experience its associated health benefits.

Supplemental Material

sj-docx-1-phr-10.1177_00333549251342889 – Supplemental material for Nonoccupational Physical Activity During Pregnancy, Behavioral Risk Factor Surveillance System, United States, 2023

Supplemental material, sj-docx-1-phr-10.1177_00333549251342889 for Nonoccupational Physical Activity During Pregnancy, Behavioral Risk Factor Surveillance System, United States, 2023 by Jasmine Y. Nakayama, Geoffrey P. Whitfield, Jennifer M. Bombard and Kelly R. Evenson in Public Health Reports®

Footnotes

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Disclaimer

The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

ORCID iDs

Jasmine Y. Nakayama, PhD

Kelly R. Evenson, PhD

Supplemental Material

Supplemental material for this article is available online. The authors have provided these supplemental materials to give readers additional information about their work. These materials have not been edited or formatted by Public Health Reports’s scientific editors and, thus, may not conform to the guidelines of the AMA Manual of Style, 11th Edition.

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