Lucas A, Cole T J, Gandy G M
Early Hum Dev. 1986 Jun;13(3):313-22. doi: 10.1016/0378-3782(86)90066-6.
The relationship between birthweight, gestation and obstetric and neonatal course was examined for 444 live births at 25-31 weeks gestation in 5 centres from 1982 to 1984 and comparative data were obtained from 121 infants below 32 weeks born in 1968-1972. The rate of 'interventive' deliveries by elective caesarean section, at this gestation, performed largely for conditions associated with poor intrauterine growth, has risen over 10-fold in the past decade, now accounting for 42% of deliveries at 30 weeks. This may explain in part a secular trend towards reduced birthweight for gestation in preterm infants. Electively delivered infants were significantly lighter than those delivered spontaneously and were responsible for substantial skewing and lowering of overall birthweight centiles. In contrast, the infant's sex, whether or not the infant survived following live birth, and whether gestational age was assessed by maternal dates or by clinical estimation (including ultrasound), all made no significant difference to birthweight centiles. A new birthweight centile chart is presented for infants less than 32 weeks, based only on spontaneous deliveries. This chart differs considerably from those commonly used in Britain and, we suggest, provides a realistic standard for identifying abnormal intrauterine growth.
1982年至1984年期间，对来自5个中心的444例孕25至31周的活产婴儿的出生体重、孕周与产科及新生儿病程之间的关系进行了研究，并从1968年至1972年出生的121例孕周小于32周的婴儿中获取了比较数据。在这个孕周，主要因与宫内生长不良相关的情况而进行的选择性剖宫产“干预性”分娩率在过去十年中上升了10倍以上，目前占30周分娩的42%。这可能在一定程度上解释了早产儿出生体重随孕周下降的长期趋势。选择性剖宫产分娩的婴儿明显比自然分娩的婴儿轻，并且导致总体出生体重百分位数大幅偏斜和降低。相比之下，婴儿的性别、出生后是否存活以及孕周是通过母亲末次月经日期还是临床评估（包括超声）来确定，对出生体重百分位数均无显著影响。本文给出了仅基于自然分娩的小于32周婴儿的新出生体重百分位数图表。该图表与英国常用的图表有很大不同，我们认为它为识别异常宫内生长提供了一个现实的标准。
