To evaluate the value of standard section quality control in improving the detection rate of fetal structural abnormality.

A total of 4742 pregnant women who underwent second-trimester obstetric ultrasound examination at our hospital from October 2018 to September 2020 were retrospectively analyzed. Taking the time of beginning to implement quality control as the cutoff point (October 2019), the included cases were divided into either a before-quality control (B-QC) group or an after-quality control (A-QC) group. A total of 36 standard sections of fetal skull, chest, abdomen, limbs, and appendages were analyzed. The number of images retained for each pregnant woman was calculated. If the images were clear and the sections were complete and accurate, the standard sections were defined as image coincidence. The χ² test was used to compare the coincidence rate of standard sections, the detection rate of fetal structural abnormality, and the rates of missing diagnosis and misdiagnosis between the two groups.

In the B-QC group, there were 47 ultrasonographic images per pregnant woman on average, and the coincidence rate of standard sections was 73%. In the A-QC group, there were 89 ultrasonographic images per pregnant woman on average, and the coincidence rate of standard sections was 89%. The detection rate of four standard sections (left plantar section, right plantar section, diaphragm coronal section, and double kidney transverse section) in the A-QC group was significantly higher than that in the B-QC group (84.5% vs 11.0%, 84.5% vs 11.0%, 91.0% vs 20.5%, and 92.5% vs 30.0%, χ²=124.831, 124.831, 201.475, and 164.582, respectively, P＜0.001 for all). Compared with the B-QC group, the coincidence rates of the horizontal transverse section of the eyes, the coronal section of the nose and lip, and the median sagittal section of the face in the A-QC group were significantly higher than those in the B-QC group (89.0% vs 53.5%, 100% vs 89.0%, and 94.0% vs 76.5%, χ²=61.523, 23.280, and 24.355, respectively, P＜0.001 for all). The coincidence rates of left ventricular outflow tract section, three-vessel section, three-vessel trachea section, and fetal heart rate section in the A-QC group were significantly higher than those in the B-QC group (93.0% vs 84.0%, 86.5% vs 61.0%, 92.0% vs 53.5%, and 95.0% vs 36.0%, χ²=7.959, 33.588, 74.769, and 154.044, respectively, P＜0.001 for all). The detection rates of fetal structural abnormality and fetal malformation in the A-QC group were significantly higher than those in the B-QC group (15.7% vs 13.3% and 1.3% vs 0.5%, χ²=7.566 and 7.571, P=0.006 and 0.006, respectively). The rates of missed and misdiagnosis were decreased (0.8% vs 0.9% and 0.2% vs 0.3%, respectively), but there was no statistical difference between the two groups (χ²=1.156 and 0.269, P=0.604 and 0.282, respectively).

The quality control of the standard sections of ultrasound can improve the coincidence rate of the standardized image retention in grade Ⅲ obstetric ultrasound examination and increase the detection rate of fetal structural abnormality, thus providing a basis for clinical decision-making.