Fetal ultrasound uses reflected sound waves to provide an image of
the fetus and placenta. Fetal ultrasound is the safest way to obtain
information about the fetus, such as its size, position, age, and
During a fetal ultrasound, a small handheld instrument called a
transducer is used to direct sound waves through the pregnant woman's abdomen.
A computer analyzes the sound waves that are reflected back from the fetus and
other structures in the uterus and converts them into an image. Fetal
ultrasound can be done by moving the transducer across the woman's abdomen
(transabdominal) or by inserting the transducer in her vagina (transvaginal).
After about the 11th week of pregnancy, almost all fetal ultrasounds are done
using the transabdominal method.
Sarah Marshall, MD - Family Medicine & William Gilbert, MD - Maternal and Fetal Medicine
The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.