Maternal and Fetal Medicine Unit, Department of Obstetrics and Gynecology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
BMC Pregnancy Childbirth. 2022 Jan 11;22(1):27. doi: 10.1186/s12884-021-04332-0.
To establish the reference ranges and evaluate the efficacy of the fetal facial sonomarkers prenasal thickness (PT), nasal bone length (NBL), PT/NBL ratio and NBL/PT ratio for Down syndrome screening in the second trimester of high-risk pregnancies using two-dimensional (2D) ultrasound.
A prospective study was done in Thai pregnant women at high risk for structural and chromosomal abnormalities between May 2018 and May 2019. The main exclusion criteria were any fetal anatomical anomaly detected on ultrasonography or postpartum examination, abnormal chromosome or syndrome other than Down syndrome. Ultrasounds were performed in 375 pregnant women at 14 to 22 weeks' gestation and the fetal facial parameters were analyzed. Down syndrome results were confirmed by karyotyping. The reference ranges of these facial ultrasound markers were constructed based on the data of our population. The Down syndrome screening performance using these facial ultrasound markers was evaluated.
In total, 340 euploid fetuses and 11 fetuses with Down syndrome met the inclusion criteria. The PT, NBL, and PT/NBL ratios in the euploid fetuses gradually increased with gestation progression while the NBL/PT ratio gradually decreased between 14-22 weeks' gestation. The NBL, PT/NBL ratio, and NBL/PT ratio all had 100% sensitivity and PT had 91% sensitivity. These facial markers had 100% negative predictive value for Down syndrome screening in the second trimester. The Bland-Altman analysis showed the intra- and inter-observer variations of PT and NBL had high intraclass correlation coefficients (ICC) in both operators, with ICCs of 0.98 and 0.99 and inter-observer ICCs of 0.99 for both operators.
The facial ultrasound markers are very useful for second trimester Down syndrome screening in our population. These facial ultrasound markers were easily identifiable and highly consistent either intra- or inter-operator by using widely-available 2D ultrasound. However, the reference ranges for these markers need to be constructed based on individual populations.
Registration number: REC 61-029-12-3. Date of registration: 18 May 2018.
使用二维（2D）超声建立中孕期高危妊娠胎儿鼻前厚度（PT）、鼻骨长度（NBL）、PT/NBL 比值和 NBL/PT 比值的参考范围，并评估其在唐氏综合征筛查中的效果。
这是一项前瞻性研究，于 2018 年 5 月至 2019 年 5 月在泰国高危结构和染色体异常的孕妇中进行。主要排除标准为超声或产后检查发现任何胎儿解剖异常、染色体异常或唐氏综合征以外的异常综合征。对 375 名 14 至 22 孕周的孕妇进行超声检查，并分析胎儿面部参数。唐氏综合征结果通过核型分析确定。根据本人群的数据构建这些面部超声标志物的参考范围。评估这些面部超声标志物在唐氏综合征筛查中的性能。
共有 340 例正常核型胎儿和 11 例唐氏综合征胎儿符合纳入标准。正常核型胎儿的 PT、NBL 和 PT/NBL 比值随孕周的进展而逐渐增加，而 NBL/PT 比值在 14-22 孕周之间逐渐下降。NBL、PT/NBL 比值和 NBL/PT 比值的敏感性均为 100%，PT 的敏感性为 91%。这些面部标志物在中孕期唐氏综合征筛查中具有 100%的阴性预测值。Bland-Altman 分析显示，两位操作者的 PT 和 NBL 的组内和组间变异均具有较高的组内相关系数（ICC），ICC 分别为 0.98 和 0.99，两位操作者的组间 ICC 分别为 0.99。
在我们的人群中，面部超声标志物非常有助于中孕期唐氏综合征筛查。这些面部超声标志物易于识别，并且由两位操作者使用广泛使用的 2D 超声均具有高度一致性。然而，这些标志物的参考范围需要根据个体人群进行构建。
注册号：REC 61-029-12-3。注册日期：2018 年 5 月 18 日。
