Diagnostic value of ultrasound scan at 16 to 18 gestational weeks in euploid fetuses with increased nuchal translucency

Abstract

Objective To investigate the diagnostic value of ultrasound scan at 16 to 18 gestational weeks in euploid fetuses with increased nuchal translucency (NT). Methods From January 2015 to June 2017, 214 fetuses diagnosed with increased NT thickness (NT ≥3.0 mm) during early pregnancy in Guangzhou Panyu Central Hospital were enrolled. Fetal chromosome karyotype analysis was carried out prenatally. Those cases with normal karyotype underwent ultrasound scan at 16-18 and 20-24 gestational weeks and their outcomes were followed up via telephone. Descriptive statistics was used for statistical analysis. Results There were 198 out of the 214 cases undergoing chromosome karyotype analysis and among them, 78 (39%) pregnancies were terminated due to chromosomal abnormalities. Out of the 107 cases with normal karyotype and successful follow-ups, 35%(37/107) had structural malformations. There were 19, 11 and 6 cases of fetal structural malformations diagnosed at 11-13+6, 16-18 and 20-24 weeks of gestational age, respectively, and the rest one was at 28 weeks. Structural deformities detected at 16-18 weeks included cleft lip and palate (n=2), cardiac malformations (n=2), spinal deformities (n=2), body deformities (n=2), diaphragmatic hernia (n=1), encephalocele (n=1) and left multicystic dysplastic kidney (n=1). About 91% (70/77) of the fetuses with normal karyotype but without abnormal ultrasound findings at 16-18 weeks were free of structural malformations and achieved good pregnant outcomes. Conclusions Ultrasound screening at 16 to 18 weeks of pregnancy can be used to detect multiple structural malformations in fetuses with increased NT and normal karyotype, which may contribute to early detection of fetal structural malformations and help gravidas and their families make timely decisions. Key words: Ultrasonography, prenatal; Nuchal translucency measurement; Pregnancy outcome