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DOI: 10.1055/s-0039-1695014
Regional Contribution of Previable Infant Deaths to Infant Mortality Rates in the United States
Funding M.K.L. received research funding from an educational grant from the University of Cincinnati, Department of Obstetrics and Gynecology Women's Health Scholars Program at the University of Cincinnati College of Medicine. E.D.F. received research funding from the Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; March of Dimes Grant 22-FY14–470.
Abstract
Objective Lack of standardization of infant mortality rate (IMR) calculation between regions in the United States makes comparisons potentially biased. This study aimed to quantify differences in the contribution of early previable live births (<20 weeks) to U.S. regional IMR.
Study Design Population-based cohort study of all U.S. live births and infant deaths recorded between 2007 and 2014 using Centers for Disease Control and Prevention's (CDC's) WONDER database linked birth/infant death records (births from 17–47 weeks). Proportion of infant deaths attributable to births <20 vs. 20 to 47 weeks, and difference (ΔIMR) between reported and modified (births ≥20 weeks) IMRs were compared across four U.S. census regions (North, South, Midwest, and West).
Results Percentages of infant deaths attributable to birth <20 weeks were 6.3, 6.3, 5.3, and 4.1% of total deaths for Northeast, Midwest, South, and West, respectively, p < 0.001. Contribution of < 20-week deaths to each region's IMR was 0.34, 0.42, 0.37, and 0.2 per 1,000 live births. Modified IMR yielded less regional variation with IMRs of 5.1, 6.2, 6.6, and 4.9 per 1,000 live births.
Conclusion Live births at <20 weeks contribute significantly to IMR as all result in infant death. Standardization of gestational age cut-off results in more consistent IMRs among U.S. regions and would result in U.S. IMR rates exceeding the healthy people 2020 goal of 6.0 per 1,000 live births.
Note
The abstract for this study was presented at the 38th Annual Meeting of the Society for Maternal-Fetal Medicine—The Pregnancy Meeting (poster presentation), January 29–February 3, 2018, Dallas, TX.
Publication History
Received: 26 May 2019
Accepted: 11 July 2019
Article published online:
03 September 2019
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