There is no injection or radiation exposure. When enhanced with a special Doppler technique, ultrasound can also capture moving blood images of the heart and large blood vessels. Technicians will apply a conducting gel to your skin and use a transducer to pass sound waves through your body and capture the echoes. Images are instantly captured on a television-like monitor and transferred to film or videotape for a radiologist to review and interpret. The exam typically takes 20-60 minutes.
Sound waves travel more easily through liquids.
Consequently, a full bladder facilitates passage of sound waves making the uterus and ovaries behind the bladder easier to see. When you eat, drink or chew gum, you introduce air into the stomach and bowel. Sound waves do not penetrate air, making it harder to see the target organs. Due to intestinal gas in the stomach and intestines, it is hard to see ulcers with ultrasounds. To date, no proven ill effects have been seen when doing regular ultrasounds on pregnant women.