Question Was the first wave of the coronavirus disease 2019 (COVID-19) pandemic associated with exacerbated racial/ethnic disparities in preterm birth in New York City?
Findings This cross-sectional study found that racial/ethnic disparities in very preterm birth and preterm birth among 8026 women were similar during the first wave of the COVID-19 pandemic in New York City compared with the same period the year prior.
Meaning Monitoring of racial/ethnic disparities in adverse birth outcomes as the COVID-19 pandemic continues is warranted.
Importance The coronavirus disease 2019 (COVID-19) pandemic may exacerbate existing racial/ethnic inequities in preterm birth.
Objective To assess whether racial/ethnic disparities in very preterm birth (VPTB) and preterm birth (PTB) increased during the first wave of the COVID-19 pandemic in New York City.
Design, Setting, and Participants This cross-sectional study included 8026 Black, Latina, and White women who gave birth during the study period. A difference-in-differences (DID) analysis of Black vs White disparities in VPTB or PTB in a pandemic cohort was compared with a prepandemic cohort by using electronic medical records obtained from 2 hospitals in New York City.
Exposures Women who delivered from March 28 to July 31, 2020, were considered the pandemic cohort, and women who delivered from March 28 to July 31, 2019, were considered the prepandemic cohort. Reverse transcription–polymerase chain reaction tests for the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were performed using samples obtained via nasopharyngeal swab at the time of admission.
Main Outcomes and Measures Clinical estimates of gestational age were used to calculate VPTB (<32 weeks) and PTB (<37 weeks). Log binomial regression was performed to estimate Black vs White risk differences, pandemic cohort vs prepandemic cohort risk difference, and an interaction term representing the DID estimator. Covariate-adjusted models included age, insurance, prepregnancy body mass index, and parity.
Results Of 3834 women in the pandemic cohort, 492 (12.8%) self-identified as Black, 678 (17.7%) as Latina, 2012 (52.5%) as White, 408 (10.6%) as Asian, and 244 (6.4%) as other or unspecified race/ethnicity, with approximately half the women 25 to 34 years of age. The prepandemic cohort comprised 4192 women with similar sociodemographic characteristics. In the prepandemic cohort, VPTB risk was 4.4% (20 of 451) and PTB risk was 14.4% (65 of 451) among Black infants compared with 0.8% (17 of 2188) VPTB risk and 7.1% (156 of 2188) PTB risk among White infants. In the pandemic cohort, VPTB risk was 4.3% (21 of 491) and PTB risk was 13.2% (65 of 491) among Black infants compared with 0.5% (10 of 1994) VPTB risk and 7.0% (240 of 1994) PTB risk among White infants. The DID estimators indicated that no increase in Black vs White disparities were found (DID estimator for VPTB, 0.1 additional cases per 100 [95% CI, −2.5 to 2.8]; DID estimator for PTB, 1.1 fewer case per 100 [95% CI, −5.8 to 3.6]). The results were comparable in covariate-adjusted models when limiting the population to women who tested negative for SARS-CoV-2. No change was detected in Latina vs White PTB disparities during the pandemic.
Conclusions and Relevance In this cross-sectional study of women who gave birth in New York City during the COVID-19 pandemic, no evidence was found for increased racial/ethnic disparities in PTB, among women who tested positive or tested negative for SARS-CoV-2.
Black women and infants experience persistent disadvantage in birth outcomes in the US. Black infants are 50% more like to be born preterm and twice as likely to be born very preterm.1 In New York City (NYC), Latina women are also at increased risk of delivering preterm.2 The coronavirus disease 2019 (COVID-19) pandemic threatens to exacerbate existing preterm birth (PTB) and very preterm birth (VPTB) disparities, yet data are scarce to inform this pressing concern.
The COVID-19 pandemic is replicating existing structures of inequality and disproportionately harming communities of color. Black and Latina women are more likely to be infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at delivery3 and more likely to experience pandemic-related psychosocial and economic impacts during pregnancy.4 Research thus far on obstetric outcomes during the pandemic typically report a modest increased risk of PTB among women with COVID-195 and little to no increased risk among women who are asymptomatic but test positive for SARS-CoV-2.6 To date, research has not adequately examined the association of the COVID-19 pandemic with PTB from a health equity perspective.
To fill this gap, we conducted a difference-in-differences (DID) analysis of electronic medical records of 8026 women from 2 hospitals in a NYC health system, which draws patients from the Bronx, Manhattan, Queens, and Brooklyn. We compared racial/ethnic differences in PTB during the first wave of the pandemic with the year prior.
We created a pandemic cohort of 3834 women who delivered between March 28, 2020, the date universal testing of women undergoing labor and delivery began, and July 31, 2020. We did not include births prior to universal testing owing to unknown SARS-CoV-2 status. We created a prepandemic cohort of 4192 women who delivered children from March 28 to July 31, 2019 (eFigure in the Supplement). We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline for cross-sectional studies. The institutional review board of the Icahn School of Medicine at Mount Sinai approved the study and waived the requirement for obtaining informed consent because risk to participants was considered minimal and the study could not reasonably been conducted otherwise. No one received compensation or was offered any incentive for participating in this study.
Reverse transcription polymerase chain reaction tests for the presence of SARS-CoV-2 were performed using samples obtained via nasopharyngeal swab. We used electronic medical records to ascertain all variables. Participant race and ethnicity were self-reported on admission and classified according to the US Office of Management and Budget standards. We estimated VPTB (<32 weeks completed gestation) and PTB (<37 weeks completed gestation) using the clinician’s best estimate of gestational age.
We used log binomial regression to estimate a DID equation with main effects for Black vs White risk difference, pandemic vs prepandemic cohort risk difference, and an interaction term representing the DID estimator. The DID estimator estimates the additional disparity resulting from the pandemic beyond disparities that had previously existed. We repeated the model for Latina vs White women, restricting the pandemic cohort to positive or negative SARS-CoV-2 test status, and singleton births. We estimated multivariable models adjusting DID estimates for age, insurance type, prepregnancy body mass index, and parity. The DID approach is typically robust to confounding given the balance of covariates between treatment groups is constant over time. In multivariable analyses, we excluded observations with missing values (<4% for body mass index, <3% for polymerase chain reaction, and <1% all others). All analyses were conducted using SAS, version 9.4 (SAS Institute Inc). A 2-sided P < .05 was considered statistically significant.
The pandemic cohort included 3834 women; 492 (12.8%) identified as Black, 678 (17.7%) as Latina, 2012 (52.5%) as White, 408 (10.6%) as Asian, and 244 (6.4%) as another or unspecified race/ethnicity (Table 1). Roughly half of women in the pandemic cohort were aged 25 to 34 years. The prepandemic cohort (n = 4192) was similar to the pandemic cohort in sociodemographic characteristics (Table 1; P > .05 for all χ2 tests). Study characteristics also did not change over time within racial/ethnic groups (Table 2). Of 3731 women in the pandemic cohort, 210 (5.6%) tested positive for SARS-CoV-2. The risk of PTB was 14.4% (65 of 451) among Black births and 7.1% (156 of 2188) among White births during the prepandemic period, and 13.2% (65 of 491) among Black births and 7.0% (140 of 1994) among White births in the pandemic cohort (Table 3). There was no change in the Black vs White PTB disparity associated with the COVID-19 pandemic (DID estimator, 1.1 fewer cases per 100 [95% CI, −5.8 to 3.6]). The risk of VPTB was 4.4% (20 of 451) among Black births and 0.8% (17 of 2188) among White births in the prepandemic period, and 4.3% (21 of 491) among Black births and 0.5% (10 of 1994) among White births in the pandemic period. The DID estimator was 0.1 (95% CI, −2.5 to 2.8), indicating no change in the Black vs White VPTB disparity. We also did not find increases in Latina vs White PTB or VPTB disparities (Table 3). Covariate-adjusted estimates were similar (Table 3). Analyses stratified by SARS-CoV-2 status found DID estimators in the SARS-CoV-2–negative group were similar to the overall cohort (Table 4). We did not conduct DID analyses in the SARS-CoV-2–positive group owing to low counts of outcomes (Table 5). The DID estimators for VPTB and PTB were similar for singleton births.
We found no evidence that the first wave of the COVID-19 pandemic increased racial/ethnic disparities in preterm birth in NYC. Results were similar by SARS-CoV-2 status.
Our findings should be considered in the context of a current hypothesis that the lockdown has lessened the risk of PTB for women.7-9 In contrast to this hypothesis, in Philadelphia, PTB did not change,10 whereas in California, VPTB increased slightly among Latina mothers.11 Unlike other recent reports,10,11 we explicitly tested racial/ethnic disparities with a robust DID design and were able to stratify our results by active SARS-CoV-2 infection.
Researchers have proposed potential reasons for a decrease in PTB during the COVID-19 pandemic, such as a decrease in known risk factors for PTB, including occupational environment, pollution, or stress.9 However, any benefit from COVID-19–related restrictions may be less prevalent among Black and Latina women in NYC, who may be more likely to be essential workers12 and to experience higher rates of COVID-19 pandemic–related stress, anxiety, and food insecurity.4,13,14 Black and Latina women are also more likely than White women to experience loss and trauma due to COVID-19.15 Decreased access to prenatal care, increased incidence of pregnancy complications, or decreased control of chronic conditions may also play a role. Despite these potential mechanisms, we did not find an increase in racial/ethnic differences in PTB. Regardless, given the known inequitable repercussions of COVID-19 in Black and Latinx populations, continued monitoring of racial/ethnic disparities in preterm birth is warranted.
The limitations of our study include the lack of information on maternal comorbidities and SARS-CoV-2 infections prior to delivery. If healthy White women disproportionately left NYC to deliver their infants during the pandemic, this selection bias would cause a greater proportion of preterm births in the White pandemic cohort, and underestimate an increase in PTB disparities. Evaluation of covariates by race/ethnicity and cohort suggested this bias was minimal. Another limitation is the lack of precision to calculate DID estimators among women who tested positive for SARS-CoV-2. Our results may not be generalizable to nonurban settings. The strengths of our study include a diverse population with a rigorous DID analysis design.
In this cross-sectional study of women who gave birth in NYC during the COVID-19 pandemic, we found no evidence of increased racial/ethnic differences in preterm birth, among women who tested positive or negative for SARS-CoV-2. However, continued monitoring of birth inequities as the pandemic continues is warranted.
Accepted for Publication: January 23, 2021.
Published: March 17, 2021. doi:10.1001/jamanetworkopen.2021.1816
Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2021 Janevic T et al. JAMA Network Open.
Concept and design: Janevic, Glazer, Stone, Howell.
Acquisition, analysis, or interpretation of data: Janevic, Glazer, Vieira, Weber, Stern, Bianco, Wagner, Dolan.
Drafting of the manuscript: Janevic, Glazer.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Janevic, Glazer, Weber, Bianco.
Administrative, technical, or material support: Vieira, Stone, Stern, Wagner, Dolan, Howell.
Supervision: Janevic, Stone, Dolan, Howell.
Conflict of Interest Disclosures: Dr Dolan reported receiving grants from the Centers for Disease Control and Prevention during the conduct of the study. No other disclosures were reported.
Funding/Support: This work was supported by the Blavatnik Family Foundation.
Role of the Funder/Sponsor: The Blavatnik Family Foundation had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
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