eAppendix. Statistical Analysis
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Cao W, Sun S, Danilack VA. Analysis of Gestational Weight Gain During the COVID-19 Pandemic in the US. JAMA Netw Open. 2022;5(9):e2230954. doi:10.1001/jamanetworkopen.2022.30954
The COVID-19 pandemic has been associated with weight gain among adults, children, and adolescents,1,2 but little is known about gestational weight gain (GWG) among pregnant individuals. Gestational weight gain is associated with important health implications for parents and offspring, and excessive GWG is associated with adverse pregnancy outcomes.3 We estimated changes in GWG among individuals giving birth to live infants during the COVID-19 pandemic in the US.
In this cross-sectional study, we obtained data on all live births in the US from January 1, 2018, to December 31, 2020, from the National Center for Health Statistics of the Centers for Disease Control and Prevention. Data analysis was performed from January 1, 2022, to July 15, 2022. We restricted our analyses to singleton births to residents and excluded births with missing gestational age, GWG, and body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) before pregnancy. Gestational weight gain was calculated by subtracting weight before pregnancy from the delivery weight. To examine vulnerable racial and ethnic groups, race and ethnicity were categorized on the basis of US birth certificate questionnaires as Hispanic, non-Hispanic Asian or non-Hispanic Pacific Islander, non-Hispanic Black, non-Hispanic White, and other race or ethnicity (including non-Hispanic American Indian or Alaskan Native, non-Hispanic with more than 1 race, and unknown or undisclosed race or ethnicity). Patient consent was waived because the study involved analysis of deidentified publicly available data and was deemed non–human participant research by the institutional review board at the Capital Medical University. This study followed the STROBE reporting guideline.
We defined the COVID-19 pandemic period as March 1 to December 31, 2020. We defined dichotomous excessive GWG as weight gain above the BMI-specific Institute of Medicine recommendations.4 We used linear regression or logistic regression to compare the GWG (continuous outcome) or excessive GWG (dichotomous outcome) among patients whose infants were born during the pandemic period vs the analogous period in 2019 (ie, referent period) after excluding prepandemic trends in GWG by comparing GWG or excessive GWG during the referent period in 2019 vs 2018 (eAppendix in the Supplement). We adjusted for gestational age, maternal age, educational attainment, race and ethnicity, marital status, adequacy of prenatal care utilization index, BMI before pregnancy, and source of delivery payment. Analyses were performed in R software, version 3.6.1 (R Foundation for Statistical Computing). A 2-sided P < .05 was considered statistically significant.
Our analysis included 2 847 592 singleton births in 2020 (mean [SD] GWG, 13.31 [6.85] kg), 2 475 822 in 2019 (mean [SD] GWG, 13.28 [6.84] kg), and 2 847 592 in 2018 (mean [SD] GWG, 13.31 [6.85] kg) (Table 1). After adjusting for covariates and excluding prepandemic trends in GWG, we observed an increase of 0.06 kg (95% CI, 0.04-0.07 kg) in GWG, with pronounced increases among pregnant individuals younger than 25 years (net change, 0.22; 95% CI, 0.19-0.26), non-Hispanic Black individuals (net change, 0.12; 95% CI, 0.07-0.16), unmarried individuals (net change, 0.16; 95% CI, 0.13-0.19), individuals who had obesity before pregnancy (net change, 0.17; 95% CI, 0.14-0.21), and individuals who used Medicaid to pay for delivery (net change, 0.17; 95% CI, 0.15-0.20) (Table 1). The pandemic was also associated with an increased risk of excessive GWG (ratio of odds ratio, 1.01; 95% CI, 1.01-1.02) (Table 2). The susceptible populations to excessive GWG were the same as for continuous GWG.
These findings suggest that the COVID-19 pandemic was associated with higher GWG and higher risk of excessive GWG among US individuals with singleton pregnancies, especially those younger than 25 years, non-Hispanic Black individuals, unmarried individuals, individuals with obesity before pregnancy, and individuals using Medicaid to pay for delivery. These findings shed light on the associations of the pandemic with adverse pregnancy outcomes5 and highlight the need to address pandemic-related GWG, particularly among vulnerable populations, to minimize the public health impact. Study limitations include self-reported height and weight before pregnancy and lack of information on COVID-19 infection on birth certificates. Future studies that identify the period of maximum association of the COVID-19 pandemic with GWG may be useful.
Accepted for Publication: July 26, 2022.
Published: September 9, 2022. doi:10.1001/jamanetworkopen.2022.30954
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2022 Cao W et al. JAMA Network Open.
Corresponding Author: Shengzhi Sun, PhD, School of Public Health, Capital Medical University, Beijing 100069, China (firstname.lastname@example.org).
Author Contributions: Dr Sun had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: All authors.
Acquisition, analysis, or interpretation of data: Sun.
Drafting of the manuscript: Cao, Sun.
Critical revision of the manuscript for important intellectual content: Sun, Danilack.
Statistical analysis: Cao, Sun.
Administrative, technical, or material support: Sun, Danilack.
Supervision: Sun, Danilack.
Conflict of Interest Disclosures: None reported.