Community violence is an understudied aspect of social context that may affect risk of preterm birth and small-for-gestational age (SGA).
We matched California mothers with live singleton births who were exposed to a homicide in their Census tract of residence in 2007–2011 to unexposed mothers within the same tract. We estimated risk differences with a weighted linear probability model, with weights corresponding to the matched data structure. We estimated the average treatment effect on the treated of homicide exposure on the risk of preterm birth and SGA during the preconception period and first and second trimester.
We found a small increase in risk of SGA associated with homicide exposure in the first trimester (0.14% [95% confidence interval (CI) = −0.01%, 0.30%]), but not for exposure during the preconception period (−0.01% [95% CI = −0.17%, 0.15%]) or the second trimester (−0.06% [95% CI = −0.23%, 0.11%]). Risk of preterm birth was not affected by homicide exposure. When women were exposed to homicides during all three exposure windows, there was a larger increase in risk of SGA (1.09% [95% CI = 0.15%, 2.03%]) but not preterm birth (0.14% [95% CI = −0.74%, 1.01%]). Exposure to three or more homicides was also associated with greater risk of SGA (0.78% [95% CI = 0.15%, 1.40%]). Negative controls indicated that residual confounding by temporal patterning was unlikely.
Homicide exposure during early pregnancy is associated with a small increased risk of SGA.
From the aDivision of Epidemiology and Biostatistics School of Public Health, University of California, Berkeley, CA
bSexual Health and Reproductive Equity Program, School of Social Welfare, University of California, Berkeley, CA.
Submitted August 27, 2018; accepted May 21, 2019.
Funding for this work was provided by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institutes of Health Office of the Director (DP2HD080350). This work was also supported by pilot grant funds from the University of California, Berkeley Committee on Research.
The authors report no conflicts of interest.
Supplemental digital content is available through direct URL citations in the HTML and PDF versions of this article (www.epidem.com).
Data and code availability: The code is available in the eAppendix. The data are confidential to protect patient privacy, but interested researchers can apply for access through California’s Department of Public Health. The link to the application form is provided in the eAppendix; http://links.lww.com/EDE/B541.
Correspondence: Dana E. Goin, Division of Epidemiology and Biostatistics School of Public Health, University of California, 2121 Berkeley Way West, Berkeley, CA 94720. E-mail: email@example.com.