Ultrasound scans, or sonography is an imaging technique based on sound waves that allows medical personnel to view a picture of the inside of the body to detect problems in the liver, heart, kidney, or abdomen, and to evaluate fetal development. Recent studies have found increased risk of autism and poorer nonverbal IQ in vulnerable fetuses when exposed to an ultrasound in the first trimester of pregnancy, detailing the mechanism to which toxic birth defects occur on the central nervous system of a developing fetus.