Using a case-based format, the ACR and ISUOG guidelines were reviewed and compared.

• Both recommend scanning all pregnancies but suggest detailed scans for high-risk cases. ACR defines high-risk as hypertension or diabetes, while ISUOG includes pregnancies from assisted reproductive technologies.
• The anatomy survey includes fetal head, face, neck, chest, abdomen, spine, extremities, and genitalia.
• Both recommend evaluating biometry (biparietal diameter, head/abdominal circumference, femur length), cardiac activity, and basic fetal anatomy (head, heart, abdomen, limbs). ISUOG adds additional views for suspected anomalies.
• For the biparietal diameter biometry this is measured at the level of the thalami and cavum septum pellucidum. The cerebellar hemispheres should not be visible in this scanning plane. The measurement is typically measured from the distal skull's inner edge to the proximal skull's outer edge.
• For the head circumference this is measured at the same level as the biparietal diameter, around the outer perimeter of the bony calvarium, excluding subcutaneous tissues of the skull. 
• The abdominal circumference is measured on a true transverse view at the level of the umbilical vein portal sinus junction and fetal stomach. The ribs should be seen.
• Femur length is measured on the long axis of the ossified femoral shaft; it is only reliable after 14 weeks. The US beam is perpendicular to the femur. No epiphysis is visualized.

For cardiac activity:

• Both recommend a four-chamber view; ISUOG advises optional outflow tract views for high-risk cases.
• ISUOG emphasizes additional views to visualize the aortic/pulmonary outflow tracts, assessing the fetal heart’s rate, size, position, and suggesting fetal echocardiography for high-risk pregnancies.

• ISUOG prefers that the single deepest pocket (SDP) (aka maximum vertical pocket  (MVP) = deepest vertical pocket (DVP)) be used for oligohydramnios and AFI be used for polyhydramnios.  ACR also prefers SDP for oligohydramnios but does not distinguish between SDP vs AFI as to which is better for polyhydramnios.  The ACR guidelines also make a specification that the SDP should at least be 1 cm wide to be accurate, which ISUOG does not mention. They both agree that SDP for oligohydramnios decreases unnecessary intervention.

• Evaluation also includes cardiac size, position, situs, and rhythm.

• Left and right ventricular outflow tracts are assessed if a more detailed heart exam is needed.
• Both emphasize placental and cord insertion evaluation. ACR focuses on screening for vasa previa and placenta accreta, while ISUOG stresses velamentous cord insertion.
• Both suggest confirming a three-vessel umbilical cord.