Department of Obstetrics and Gynecology, Assaf Harofe Medical Center, affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Israel.
Ultrasound Obstet Gynecol. 2009 Dec;34(6):629-33. doi: 10.1002/uog.7480.
To construct tables for 'bedside' estimation of Down syndrome risk based on maternal age and ultrasound prenasal thickness (PT) measurements.
Likelihood ratios were calculated using a log Gaussian model of the PT distribution in multiples of the gestational age-specific median (MoM). The model parameters were derived from 80 Down syndrome and 850 unaffected pregnancies scanned at 14-27 weeks; these data had been published previously, in three series, except for 18 Down syndrome and 119 affected pregnancies. The means were estimated as the median, and the SDs as the 10(th)-90(th) range divided by 2.563.
A log Gaussian model fitted well the distribution of PT values in Down syndrome and unaffected pregnancies with medians of 1.31 MoM and 1.01 MoM, and log(10) SDs of 0.075 and 0.082, respectively.
The tables provide a simple 'bedside' estimation of Down syndrome risk without the need for computerized software or complicated calculations. More prospective data on PT in combination with other first- and second-trimester screening markers are needed.
基于孕妇年龄和超声鼻骨厚度（PT）测量值，构建用于“床边”估计唐氏综合征风险的表格。
使用 PT 分布在多个妊娠龄中位数（MoM）上的对数正态模型计算似然比。该模型参数是从 80 例唐氏综合征和 850 例无影响妊娠的扫描数据中得出的，这些数据先前已在三个系列中发表过，除了 18 例唐氏综合征和 119 例受影响的妊娠。平均值估计为中位数，标准差为第 10 至 90 个百分位数除以 2.563。
对数正态模型很好地拟合了唐氏综合征和无影响妊娠的 PT 值分布，中位数分别为 1.31 MoM 和 1.01 MoM，对数（10）SD 分别为 0.075 和 0.082。
这些表格提供了一种简单的“床边”唐氏综合征风险估计方法，无需使用计算机软件或复杂的计算。需要更多关于 PT 与其他第一和第二孕期筛查标志物的前瞻性数据。
