Normal diameter of the main pulmonary artery in fetuses

The normal diameter of the fetal main pulmonary artery is generally 2–5 mm.

The diameter of the fetal aorta varies with gestational age. Since fetal cardiac imaging is performed using ultrasound, during weeks 24 to 28 of pregnancy, the fetal heart reaches a moderate size and its internal structures become relatively clear, allowing for well-defined cardiac images via ultrasound. The normal diameter of the main pulmonary artery at this stage is typically observed to be 2–5 mm.

A detailed color Doppler ultrasound examination is recommended during the second trimester. If any abnormalities are detected, further evaluation at a hospital is necessary to determine whether congenital heart defects are present. For cases associated with severe pulmonary vascular stenosis, appropriate medical intervention must be provided.

It should be noted that the measured diameter of the fetal aorta increases with gestational age, so measurements must be interpreted in conjunction with the specific gestational week. A balanced diet rich in high-protein and high-vitamin foods is recommended. Smoking and alcohol consumption should be avoided. Maintaining a positive mental state and avoiding stress, anxiety, or depression is important to prevent adverse effects on fetal health.