Objective To explore the prenatal diagnostic value of ultrasound structural screening combined with fetal cardiac function assessment for fetuses with normal karyotype and thickening nuchal translucency (NT) at 16-18 weeks.

Methods A total of 98 fetuses with NT thickening (≥3.3 mm) indicated by ultrasound examination were selected as the research subjects. All cases were detected by ultrasound structural screening and echocardiography, and the results were compared with those of physical examination/autopsy.

Results The ultrasound results in the early stage of pregnancy showed that the average NT of the fetus was 5.4 mm (3.3-10.7 mm). Among the 98 pregnant women, 92 cases underwent prenatal karyotype analysis. Among them, 18 cases were found to have chromosomal abnormalities, and their pregnancies were terminated. While the remaining 74 cases had normal chromosomes, and were successfully followed up. Among 74 pregnant women with normal chromosomes, 25 cases of structural malformations were detected from 11 to 24 weeks of gestation, and all chose to terminate the pregnancy. The remaining 49 cases showed no abnormalities in ultrasound, and all delivered smoothly. The sensitivity of ultrasound examination in diagnosing fetal structural malformations was 88.89%, the specificity was 97.87%, the accuracy rate was 94.59%, the misdiagnosis rate was 2.13%, the missed diagnosis rate was 11.11%, the positive predictive value was 96.00%, and the negative predictive value was 93.88%.

Conclusions Ultrasound structural screening combined with cardiac function assessment can effectively identify the most structural malformations in fetuses with normal chromosomes and thickening NT at 16-18 weeks, and detect fetal structural abnormalities in advance.