Cogswell M E, Yip R
Maternal and Child Health Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Semin Perinatol. 1995 Jun;19(3):222-40. doi: 10.1016/s0146-0005(05)80028-x.
This review of common risk factors for low birthweight emphasizes the usefulness of examining the entire distribution of birthweight. Of the factors we examined, only short gestational age seemed to affect the low end of the birthweight distribution in the form of skewness. Most factors, such as maternal race, infant sex, plurality, altitude, education, and smoking seem to affect the entire birthweight distribution, indicating a generalized effect. With the exceptions of race, infant sex, parity, and altitude, these factors seemed to have similar associations with both low birthweight and infant mortality. However, only the effects of race and sex on mortality have been repeatedly studied in detail for different combinations of gestational age and birthweight. A few of the factors examined, notably infant sex and parity, have opposite associations with birthweight and infant mortality. Female infants and firstborn infants have lower birthweights than their counterparts, but are more likely to survive. For factors that significantly affect the birthweight distribution, but do not affect mortality equally across the birthweight distribution, the development and use of population-based standards may result in less misclassification of IUGR. Separate standards by infant sex, altitude, and perhaps race may lead to more accurate classification of intrauterine growth. Last, the majority of risk factors have differential effects on birthweight depending on the level of the associated factors. For example, low maternal age and low prepregnancy BMI are associated with both increased risk of low birthweight and poor infant survival. Older maternal age and high prepregnancy BMI are associated with reduced risk of low birthweight, but with increased risk of infant mortality. One possible explanation is that young maternal age and low prepregnancy BMI are associated with adverse behavioral risk factors such as cigarette smoking, whereas increased age and high prepregnancy BMI are associated with gestational diabetes, multiparity, and genetic defects. It is possible that the greater variation in birthweight at the high end of the scale is indicative of increased risk of mortality. Thus, higher birthweight does not always equal better birth outcomes.
这篇关于低出生体重常见风险因素的综述强调了研究出生体重整个分布情况的有用性。在我们研究的因素中，只有孕周短似乎以偏态的形式影响出生体重分布的低端。大多数因素，如母亲种族、婴儿性别、多胎情况、海拔、教育程度和吸烟，似乎会影响整个出生体重分布，表明存在普遍影响。除了种族、婴儿性别、产次和海拔外，这些因素与低出生体重和婴儿死亡率的关联似乎相似。然而，只有种族和性别对死亡率的影响针对不同孕周和出生体重的组合进行了反复详细研究。所研究的一些因素，特别是婴儿性别和产次，与出生体重和婴儿死亡率的关联相反。女婴和头胎婴儿的出生体重低于其对应情况，但存活可能性更大。对于那些显著影响出生体重分布但在整个出生体重分布中对死亡率影响不均等的因素，基于人群标准的制定和使用可能会减少宫内生长受限（IUGR）的错误分类。按婴儿性别、海拔以及可能按种族制定单独标准可能会导致更准确的宫内生长分类。最后，大多数风险因素对出生体重的影响因相关因素水平而异。例如，母亲年龄小和孕前体重指数低与低出生体重风险增加和婴儿存活率低均相关。母亲年龄大及孕前体重指数高与低出生体重风险降低相关，但与婴儿死亡率增加相关。一种可能的解释是，母亲年龄小和孕前体重指数低与吸烟等不良行为风险因素相关，而年龄增加和孕前体重指数高与妊娠期糖尿病、多胎妊娠和遗传缺陷相关。有可能在较高体重端出生体重的更大差异表明死亡率风险增加。因此，较高的出生体重并不总是等同于更好的出生结局。
