The answer to this question would be: ultrasound and amniocentesis
A cell that dividing frequently like fetus is at more risk when exposed to radiation from CT scan or CXR.
Ultrasound is a noninvasive procedure that will not expose the fetus to radiation. It can visualize the fetus and even measure them. With amniocentesis, we can get a sample of the fetus cell. Examining the gene of the fetus could exclude genetic disorder.
