To explore prenatal echocardiographic features of tetralogy of Fallot (TOF) with unilateral absence of the pulmonary artery (UAPA).

Fetal echocardiography was performed in 177 fetuses with tetralogy of Fallot in Hebei Maternity Hospital from October 2017 to December 2020, including four cases with UAPA. The echocardiographic data of four fetuses with TOF and UAPA were analyzed retrospectively.

The incidence of UAPA in fetuses with TOF was 2.26% (4/177). The left pulmonary artery was absent in three cases and the right pulmonary artery was absent in one case. All of the four fetuses with TOF and UAPA have typical echocardiographic manifestations of TOF including subaortic ventricular septal defect, pulmonary stenosis, and aorta overriding. The sonographic feature of UAPA in the four fetuses was the disappearance of '8-figure' structure on the pulmonary artery bifurcation view. The proximal left pulmonary arteries cannot be detected in three cases with unilateral absence of the left pulmonary artery on this view. On coronal view of the aortic arch, the left pulmonary artery branches were showed to be connected with the ventral side of the aortic arch by the ductus arteriosus in three cases. The proximal right pulmonary arteries cannot be detected in one case with unilateral absence of the right pulmonary artery on pulmonary artery bifurcation view and the right pulmonary artery branches were showed to be connected with the descending aorta. One case with unilateral absence of the left pulmonary artery had persistent left superior vena cava and atrial septal defect additionally. The case with unilateral absence of the right pulmonary artery had a right aortic arch with mirrored branches additionally.

It is of great significance to understander the prenatal echocardiographic features of TOF with UAPA in order to improve the detection rate of this disease and provide a scientific basis for families to make decisions on pregnancy.