Etiologies of fetal growth restriction
Etiologies of fetal growth restriction
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DOI：
10.1097/00003081-199712000-00006
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发表时间：
1997-12-01
影响因子：
1.5
通讯作者：
Divon, MY
中科院分区：
文献类型：
--
作者：
Bernstein, PS;Divon, MY
为了了解胎儿生长受限(FGR)的病因，有必要明确定义这个术语。从统计学的角度来看，只有同胎龄出生的婴儿体重低于平均值两个标准差才被视为异常生长，即生长受限；然而，从临床的角度来看，出生时体重低于其胎龄的10%的婴儿通常被标记为生长受限。临界值是基于人群标准确定的，选择更广泛的临床定义是为了提高定义的敏感性，以确定所有面临生长受限继发不良结局风险的婴儿。然而，这两种定义都有几个显著的局限性，随后对FGR原因研究的准确性产生了影响。首先，因为定义是特定于胎龄的，这种诊断的任何分配都需要准确的胎龄知识。其次，它要求测量的变量，在这种情况下，重量，与特定人口的适当标准数据进行比较。第三，使用这些定义会导致重大错误，因为它无法识别体重在正常范围内但实际上由于未能达到潜在出生体重而受到生长限制的新生儿。这些定义还错误地将基因较小但其他方面正常发育的婴儿列为生长受限婴儿。因此，FGR定义中对出生体重的强调降低了识别真正的生长受限婴儿的敏感性和特异性。最后，不同胎龄胎儿体重的标准数据是基于对出生体重的观察。这些数据可能会被这样一个事实所扭曲，即早产婴儿更有可能发育不正常，因此，早期妊娠的标准数据可能包括比实际人口多得多的生长受限婴儿。因此，在早期妊娠中，标准化数据应该来自分娩前没有受到生长限制影响的婴儿的出生体重。1在考虑FGR的可能病因时，必须牢记这些问题。
To understand the etiologies of fetal growth restriction (FGR), it is necessary to clearly define the term. From a statistical standpoint, only infants weighing less than two standard deviations below the mean for those born at the same gestational age are considered abnormally grown, ie growth restricted; however, from a clinical standpoint, infants born weighing less than the tenth percentile for their gestational age generally are labeled as growth restricted. The cutoff values are determined based on population-based standards, and the broader clinical definition was chosen to improve the sensitivity of the definition to identify all infants at risk for untoward outcomes secondary to growth restriction.Both of these definitions, however, have several significant limitations, with subsequent implications on the veracity of studies of causes of FGR. First, because the definitions are gestational age-specific, any assignment of this diagnosis requires accurate knowledge of the gestational age. Second, it requires that the measured variable, in this case, weight, be compared with the appropriate normative data for the given population. Third, the use of these definitions introduces significant error because it fails to identify those newborns whose weights fall within the normal range, but who are in fact growth restricted because they failed to attain their potential birthweight. These definitions also incorrectly label as growth restricted infants who are genetically small but otherwise normally grown. Thus, the emphasis on birthweight in the definition of FGR reduces the sensitivity and specificity of the identification of truly growth-restricted infants. Finally, the normative data for fetal weight at various gestational ages are based on observations of birthweights. These data may be skewed by the fact that prematurely born infants are more likely to be abnormally grown and, therefore, the normative data for the earlier gestations may include many more growth-restricted babies than the actual population. In earlier gestations, therefore, normative data should be derived from birthweights of infants who were not exposed to growth restricting influences before delivery. 1 These issues must be kept in mind when considering possible etiologies of FGR.