Reliability of ultrasound dating
Some abnormalities detected by ultrasound can be addressed by medical treatment in utero or by perinatal care, though indications of other abnormalities can lead to a decision regarding abortion.
Perhaps the most common such test uses a measurement of the nuchal translucency thickness ("NT-test", or "Nuchal Scan").
Randomized controlled trials have followed children up to ages 8–9, with no significant differences in vision, hearing, school performance, dyslexia, or speech and neurologic development by exposure to ultrasound.
Several randomized controlled trials have reported no association between Doppler exposure and birth weight, Apgar scores, and perinatal mortality.
Obstetric ultrasonography is the use of medical ultrasonography in pregnancy, in which sound waves are used to create real-time visual images of the developing embryo or fetus in its mother's uterus (womb).
This includes checking the status of the limbs and vital organs, as well as (sometimes) specific tests for abnormalities. The bright white circle center-right is the head, which faces to the left.Features include the forehead at 10 o'clock, the left ear toward the center at 7 o'clock and the right hand covering the eyes at .Not useful for dating, the abdominal circumference of the fetus may also be measured.
This gives an estimate of the weight and size of the fetus and is important when doing serial ultrasounds to monitor fetal growth.
This was the start of the most popular design in the history of ultrasound scanners.