Department of Obstetrics and Gynecology, Hillel Yaffe Medical Center, Hadera 38100, Israel.
The Ruth and Bruce Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Haifa, Israel.
J Perinat Med. 2019 Sep 25;47(7):757-764. doi: 10.1515/jpm-2019-0207.
Objective To construct new reference values for biometrical measurements and sonographic estimated fetal weight (sEFW) in twin gestations and compare them to previously published normograms. Methods A retrospective analysis of sEFW evaluations of twin gestations was performed between 2011 and 2016 in a single university-affiliated medical center. sEFW was calculated using the Hadlock 1985 formula. To avoid selection bias, one evaluation per pregnancy was randomly selected. Following mathematical transformation to obtain normality of values, normograms were constructed using a best-fit regression model for estimation of mean and standard deviation at each gestational age (GA). Normograms were validated by applying all observations to ensure equal distribution at parallel percentiles. Our normograms were then compared to previously published sEFW normograms for twin gestations. Results A total of 864 sEFW evaluations were performed on 195 twin pregnancies at 22-39 gestational weeks. Of them, 390 entered the primary analysis. The rest were left for validation. Seventy percent of the cohort were dichorionic-diamniotic twins (136/195), 16% (32/195) were monochorionic-diamniotic twins and three (1.5%) were monochorionic-monoamniotic twins. Twenty-four fetuses lacked data on chorionicity. The rest were monochorionic twins or were of unknown chorionicity. Values corresponding to the 2.5th, 10th, 50th, 90th and 97.5th percentiles for sEFW are presented for every GA. Validation by applying all 864 evaluations on constructed normograms was achieved. Comparison to previously published twins' sEFW normograms demonstrated wide variation between curves. Conclusion New reference values for biometrical measurements and sEFW in twin gestations are presented for clinical and research use. Comparison to other curves demonstrates the wide variability and need for further investigation on twin's normal growth.
构建新的双胎妊娠生物测量值和超声估测胎儿体重（sEFW）参考值，并与已发表的标准曲线进行比较。方法：对 2011 年至 2016 年期间在一家大学附属医院进行的双胎妊娠 sEFW 评估进行回顾性分析。使用 Hadlock 1985 公式计算 sEFW。为避免选择偏倚，每个妊娠随机选择一次评估。在对数值进行数学转换以获得正态性后，使用最佳拟合回归模型构建每个胎龄（GA）的均值和标准差估计值的标准曲线。通过将所有观察值应用于标准曲线验证来确保平行百分位数的均等分布。然后，将我们的标准曲线与已发表的双胎妊娠 sEFW 标准曲线进行比较。结果：在 22-39 孕周对 195 例双胎妊娠进行了 864 次 sEFW 评估。其中，390 次进入主要分析。其余的用于验证。队列的 70%为双绒毛膜-双羊膜双胎（136/195），16%（32/195）为单绒毛膜-双羊膜双胎，3 例（1.5%）为单绒毛膜-单羊膜双胎。24 例胎儿缺少关于绒毛膜性的数据。其余的为单绒毛膜双胎或绒毛膜性未知。每个 GA 均呈现 sEFW 第 2.5、10、50、90 和 97.5 百分位的相应值。通过将所有 864 次评估应用于构建的标准曲线，实现了验证。与已发表的双胎 sEFW 标准曲线比较显示，曲线之间存在广泛差异。结论：为临床和研究用途提供了新的双胎妊娠生物测量值和 sEFW 参考值。与其他曲线的比较表明，双胎正常生长存在广泛的变异性，需要进一步研究。
