machines rely on what is known as the Doppler effect to see various tissue types for many purposes including during prenatal exams. The Doppler effect describes the way that waves interact with various tissues (dense fluids reflect waves in a different manner than other tissue types) and the Doppler machine uses sound waves and special calculations to make these differentiations. The machine is then able to put together the information it receives and produces an image of the baby that can be either two dimensional or three dimensional. As the machine uses sound waves to reflect off the baby and evaluate those waves to produce an image, the machine is not producing harmful effects on the baby. Ultrasound is a safe and noninvasive measure that can be very useful for gynecologists and pediatricians
to assess your baby for any prenatal concerns in your baby. Unlike ct scans which use x rays to produce an image which have been shown to cause harm to babies, there is no evidence that ultrasounds can have any long lasting adverse effects on your baby. Your ob/gym will be able to give you more information about the benefits of ultrasound machines when evaluating your baby for various prenatal concerns.