Abstract：
BACKGROUND: The assessment of birthweight for gestational age and the identification of small- and large-for-gestational age (SGA and LGA) infants remain contentious, despite the recent creation of the Intergrowth 21st Project and World Health Organisation (WHO) birthweight-for-gestational age standards.
OBJECTIVE: We carried out a study to identify birthweight-for-gestational age cut-offs, and corresponding population-based, Intergrowth 21st and WHO centiles associated with higher risks of adverse neonatal outcomes, and to evaluate their ability to predict serious neonatal morbidity and neonatal mortality (SNMM) at term gestation.
METHODS: The study population was based on non-anomalous, singleton live births between 37 and 41 weeks\' gestation in the United States from 2003 to 2017. SNMM included 5-min Apgar score <4, neonatal seizures, need for assisted ventilation, and neonatal death. Birthweight-specific SNMM was modelled by gestational week using penalised B-splines. The birthweights at which SNMM odds were minimised (and higher by 10%, 50% and 100%) were estimated, and the corresponding population, Intergrowth 21st, and WHO centiles were identified. The clinical performance and population impact of these cut-offs for predicting SNMM were evaluated.
RESULTS: The study included 40,179,663 live births and 991,486 SNMM cases. Among female singletons at 39 weeks\' gestation, SNMM odds was lowest at 3203 g birthweight, and 10% higher at 2835 g and 3685 g (population centiles 11th and 82nd, Intergrowth centiles 17th and 88th and WHO centiles 15th and 85th). Birthweight cut-offs were poor predictors of SNMM, for example, the cut-offs associated with 10% and 50% higher odds of SNMM among female singletons at 39 weeks\' gestation resulted in a sensitivity, specificity, and population attributable fraction of 12.5%, 89.4%, and 2.1%, and 2.9%, 98.4% and 1.3%, respectively.
CONCLUSIONS: Reference- and standard-based birthweight-for-gestational age indices and centiles perform poorly for predicting adverse neonatal outcomes in individual infants, and their associated population impact is also small.
OBJECTIVE: We carried out a study to identify birthweight-for-gestational age cut-offs, and corresponding population-based, Intergrowth 21st and WHO centiles associated with higher risks of adverse neonatal outcomes, and to evaluate their ability to predict serious neonatal morbidity and neonatal mortality (SNMM) at term gestation.
METHODS: The study population was based on non-anomalous, singleton live births between 37 and 41 weeks\' gestation in the United States from 2003 to 2017. SNMM included 5-min Apgar score <4, neonatal seizures, need for assisted ventilation, and neonatal death. Birthweight-specific SNMM was modelled by gestational week using penalised B-splines. The birthweights at which SNMM odds were minimised (and higher by 10%, 50% and 100%) were estimated, and the corresponding population, Intergrowth 21st, and WHO centiles were identified. The clinical performance and population impact of these cut-offs for predicting SNMM were evaluated.
RESULTS: The study included 40,179,663 live births and 991,486 SNMM cases. Among female singletons at 39 weeks\' gestation, SNMM odds was lowest at 3203 g birthweight, and 10% higher at 2835 g and 3685 g (population centiles 11th and 82nd, Intergrowth centiles 17th and 88th and WHO centiles 15th and 85th). Birthweight cut-offs were poor predictors of SNMM, for example, the cut-offs associated with 10% and 50% higher odds of SNMM among female singletons at 39 weeks\' gestation resulted in a sensitivity, specificity, and population attributable fraction of 12.5%, 89.4%, and 2.1%, and 2.9%, 98.4% and 1.3%, respectively.
CONCLUSIONS: Reference- and standard-based birthweight-for-gestational age indices and centiles perform poorly for predicting adverse neonatal outcomes in individual infants, and their associated population impact is also small.
摘要：
背景：胎龄出生体重的评估以及胎龄小和胎龄大（SGA和LGA）婴儿的鉴定仍然存在争议，尽管最近创建了Intergrowth21st项目和世界卫生组织（WHO）出生体重胎龄标准。
目的：我们进行了一项研究，以确定出生体重与胎龄之间的界限，以及相应的以人口为基础的，21岁间生和WHO百分位数与新生儿不良结局的高风险相关，并评估其预测足月妊娠严重新生儿发病率和新生儿死亡率（SNMM）的能力。
方法：研究人群基于非异常，2003年至2017年，美国妊娠37至41周的单胎活产婴儿。SNMM包括5分钟Apgar评分<4，新生儿癫痫发作，需要辅助通风，新生儿死亡。出生体重特异性SNMM使用惩罚的B样条按孕周建模。SNMM赔率最小化的出生体重(并提高10%，50%和100%)估计，以及相应的人口，共生21号，并确定了世卫组织的百分位数。评估了预测SNMM的这些截止值的临床表现和人群影响。
结果：该研究包括40,179,663例活产和991,486例SNMM病例。在怀孕39周的女性单身人士中，SNMM的赔率最低，为3203克出生体重，在2835克和3685克(第11和82克的百分位数，共生百分位第17和88位以及世界卫生组织百分位第15和85位）。出生体重截止是SNMM的不良预测因子，例如,在妊娠39周时，女性单身人士中SNMM的几率分别高10%和50%，这导致了敏感性，特异性，人口归因比例为12.5%，89.4%,和2.1%，和2.9%，98.4%和1.3%，分别。
结论：基于参考和标准的出生体重胎龄指数和百分位数在预测个别婴儿的不良新生儿结局方面表现不佳，与之相关的人口影响也很小。
目的：我们进行了一项研究，以确定出生体重与胎龄之间的界限，以及相应的以人口为基础的，21岁间生和WHO百分位数与新生儿不良结局的高风险相关，并评估其预测足月妊娠严重新生儿发病率和新生儿死亡率（SNMM）的能力。
方法：研究人群基于非异常，2003年至2017年，美国妊娠37至41周的单胎活产婴儿。SNMM包括5分钟Apgar评分<4，新生儿癫痫发作，需要辅助通风，新生儿死亡。出生体重特异性SNMM使用惩罚的B样条按孕周建模。SNMM赔率最小化的出生体重(并提高10%，50%和100%)估计，以及相应的人口，共生21号，并确定了世卫组织的百分位数。评估了预测SNMM的这些截止值的临床表现和人群影响。
结果：该研究包括40,179,663例活产和991,486例SNMM病例。在怀孕39周的女性单身人士中，SNMM的赔率最低，为3203克出生体重，在2835克和3685克(第11和82克的百分位数，共生百分位第17和88位以及世界卫生组织百分位第15和85位）。出生体重截止是SNMM的不良预测因子，例如,在妊娠39周时，女性单身人士中SNMM的几率分别高10%和50%，这导致了敏感性，特异性，人口归因比例为12.5%，89.4%,和2.1%，和2.9%，98.4%和1.3%，分别。
结论：基于参考和标准的出生体重胎龄指数和百分位数在预测个别婴儿的不良新生儿结局方面表现不佳，与之相关的人口影响也很小。
