双绒毛膜双轨迹-NICHD胎儿生长的研究

双绒毛膜双轨迹-NICHD胎儿生长的研究
Dichorionic twin trajectories- the NICHD Fetal Growth Studies

Abstract
摘要
BACKGROUND:
背景：
Systematic evaluation and estimation of growth trajectories in twins require ultrasound measurements across gestation that are performed in controlled clinical settings. Currently, there are few such data for contemporary populations. There is also controversy about whether twin fetal growth should be evaluated with the use of the same benchmarks as singleton growth.
系统评估和估计的增长轨迹在双胞胎需要超声测量在妊娠期，在控制的临床设置。目前，很少有这样的数据为当代人群。也有争议是否双胎胎儿的生长应评估与使用相同的基准作为单增长。

OBJECTIVES:
目标:
Our objective was to define the trajectory of fetal growth in dichorionic twins empirically using longitudinal 2-dimensional ultrasonography and to compare the fetal growth trajectories for dichorionic twins with those based on a growth standard that was developed by our group for singletons.
我们的目的是确定双绒毛膜双胎的经验使用纵向二维超声诊断胎儿生长轨迹和比较胎儿的成长轨迹与那些基于双绒毛膜双胎的生长标准，由本集团单独开发的。

STUDY DESIGN:
研究设计：
A prospective cohort of 171 women with twin gestations was recruited from 8 US sites from 2012-2013. After an initial sonogram at 11 weeks 0 days-13 weeks 6 days of gestation during which dichorionicity was confirmed, women were assigned randomly to 1 of 2 serial ultrasonography schedules. Growth curves and percentiles were estimated with the use of linear mixed models with cubic splines. Percentiles were compared statistically at each gestational week between the twins and 1731 singletons, after adjustment for maternal age, race/ethnicity, height, weight, parity, employment, marital status, insurance, income, education, and infant sex. Linear mixed models were used to test for overall differences between the twin and singleton trajectories with the use of likelihood ratio tests of interaction terms between spline mean structure terms and twin-singleton indicator variables. Singleton standards were weighted to correspond to the distribution of maternal race in twins. For those ultrasound measurements in which there were significant global tests for differences between twins and singletons, we tested for week-specific differences using Wald tests that were computed at each gestational age. In a separate analysis, we evaluated the degree of reclassification in small for gestational age, which was defined as <10th percentile that would be introduced if fetal growth estimation for twins was based on an unweighted singleton standard.
一个171例双胎妊娠的前瞻性队列研究从2012-2013年8个美国网站招募。在11周后的最初0天图-13周6天妊娠期间，绒毛膜证实，妇女被随机分配到1个2系列超声检查时间表。与三次样条曲线的线性混合模型的估计使用生长曲线和百分位数。百分位数统计比较各孕周的双胞胎和1731个之间，产妇年龄调整后，种族、身高、体重、胎次、就业、婚姻状况、保险、收入、教育、和婴儿性别。线性混合模型被用来测试的双和单点轨迹之间的整体差异，使用的似然比检验的样条平均结构项和双单例指标变量之间的相互作用条款。独生子女标准进行加权，以对应于在双胞胎的产妇种族的分布。对于超声测量中有单胎和双胎之间的差异显着的全球测试，我们测试了一周的具体差异使用，计算在各孕周的Wald检验。在一个单独的分析，我们评估胎龄小的重新分类的程度，这被定义为小于第十百分位数，会介绍如果双胞胎胎儿生长的估计是基于一个单一的标准加权。

RESULTS:
结果:
Women underwent a median of 5 ultrasound scans. The 50th percentile abdominal circumference and estimated fetal weight trajectories of twin fetuses diverged significantly beginning at 32 weeks of gestation; biparietal diameter in twins was smaller from 34-36 weeks of gestation. There were no differences in head circumference or femur length. The mean head circumference/abdominal circumference ratio was progressively larger for twins compared with singletons beginning at 33 weeks of gestation, which indicated a comparatively asymmetric growth pattern. At 35 weeks of gestation, the average gestational age at delivery for twins, the estimated fetal weights for the 10th, 50th, and 90th percentiles were 1960, 2376, and 2879 g for dichorionic twins, respectively, and 2180, 2567, and 3022 g for the singletons, respectively. At 32 weeks of gestation, the initial week when the mean estimated fetal weight for twins was smaller than that of singletons, 34% of twins would be classified as small for gestational age with the use of a singleton, non-Hispanic white standard. By 35 weeks of gestation, 38% of twins would be classified as small for gestational age.
妇女接受了中位数的5个超声扫描。第五十个百分位数的腹围，估计胎儿体重轨迹的双胞胎胎儿分歧明显开始在妊娠32周；在双胞胎胎儿双顶径较小从34-36周妊娠。在头周或股骨长度无显着差异。平均头围、腹围比较大的双胞胎和单胎初孕33周相比，这表明相对对称的增长模式。在妊娠35周，分娩双胞胎的平均孕周、估计胎儿体重的第十，第五十，和第九十的百分位数分别为1960，2376，和2879克双卵双胎，分别为2180，2567，和3022克的单身者，分别地。在妊娠32周，最初的一周时的平均的估计胎儿体重的双胞胎比单身人士，34%对双胞胎将分为小于胎龄儿与单独使用，非西班牙裔白人的标准。在怀孕35周时，38%的双胞胎会被列为小于胎龄儿。

CONCLUSION:
结论：
The comparatively asymmetric growth pattern in twin gestations, initially evident at 32 weeks of gestation, is consistent with the concept that the intrauterine environment becomes constrained in its ability to sustain growth in twin fetuses. Near term, nearly 40% of twins would be classified as small for gestational age based on a singleton growth standard.
在双胎妊娠较为对称的增长模式，初步显现在妊娠32周，是一致的概念，宫内环境变得受限于它的能力，以维持生长的双胞胎胎儿。近期，近40%的双胞胎将被列为小胎龄的一个单一的增长标准。

原文：
Dichorionic twin trajectories- the NICHD Fetal Growth Studies.pdf (1.43 MB, 下载次数: 0, 售价: 99 香叶)

2016-9-15 09:58 上传

点击文件名下载附件
Dichorionic twin trajectories- the NICHD Fetal Growth Studies