Department of Obstetrics and Gynecology, University of Cincinnati College of Medicine, Cincinnati, Ohio.
Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
Am J Perinatol. 2021 Jan;38(2):158-165. doi: 10.1055/s-0039-1695014. Epub 2019 Sep 3.
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.
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).
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, < 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.
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.
美国各地区婴儿死亡率（IMR）计算方法缺乏标准化，使得比较结果可能存在偏差。本研究旨在量化美国各地区早期极早产儿（<20 周）对 IMR 的贡献差异。
这是一项基于人群的队列研究，使用疾病控制与预防中心（CDC）的 WONDER 数据库，对 2007 年至 2014 年间所有美国活产儿和婴儿死亡记录进行分析，这些记录与出生/婴儿死亡记录相关联（出生时 17-47 周）。<20 周与 20-47 周出生婴儿死亡的归因比例以及报告的 IMR 与修正（≥20 周出生）IMR 之间的差异（ΔIMR）在四个美国人口普查区（北部、南部、中西部和西部）之间进行比较。
<20 周出生婴儿死亡归因比例分别为东北部、中西部、南部和西部总死亡人数的 6.3%、6.3%、5.3%和 4.1%，<0.001。<20 周死亡对每个地区 IMR 的贡献分别为每 1000 例活产儿 0.34、0.42、0.37 和 0.2。修正后的 IMR 使各地区的变异程度降低，每 1000 例活产儿的 IMR 分别为 5.1、6.2、6.6 和 4.9。
<20 周的活产儿对 IMR 有显著贡献，因为所有活产儿都导致婴儿死亡。将胎龄截止值标准化可使美国各地区的 IMR 更加一致，这将导致美国的 IMR 率超过健康人 2020 年每 1000 例活产儿 6.0 的目标。
