What is the Purpose of a Fetal Ultrasound?
A fetal ultrasound is a diagnostic procedure that uses high-frequency sound waves to produce images on a monitor of your reproductive organs and fetus. It may be used to confirm pregnancy, detect specific abnormalities, and determine with impressive accuracy - between 3-5 days - the time of conception.
How is an Ultrasound Performed?
There are two forms of fetal ultrasound available:
- Transvaginal Ultrasound: Also called an endovaginal ultrasound, a transvaginal ultrasound entails the insertion of a thin wand-like transducer into the vagina, about 2-3 inches. The probe is protected with a condom and covered with gel. The probe emits high-frequency sound waves that reflect off the body's structures and are transmitted to a computer. There they are converted into images and projected onto a monitor. This method of ultrasound is usually performed with your bladder empty or partly filled. The procedure may cause minimal discomfort, but is not painful. Transvaginal ultrasounds are used most often during early pregnancy when the uterus and fallopian tubes are closer to the vagina than to the surface of the abdomen.
- Abdominal Ultrasound: This form of ultrasound uses the same high-frequency sound wave technology as a transvaginal ultrasound. But rather than a vaginal probe, a transducer is glided across the abdomen. For a transabdominal ultrasound, you'll lie on the exam table with your abdomen exposed. The technician applies a special gel to your abdomen to improve conduction. Then the technician moves the transducer across your belly. Abdominal ultrasounds are usually performed with the patient’s bladder full. This helps produce the sharpest images possible. Abdominal fetal ultrasounds are usually used during the latter parts of your pregnancy.
Can an Ultrasound Cause Harmful Side Effects?
Ultrasounds are considered extremely safe. They have been used routinely in gynecology and obstetrics since the 1950s. Unlike traditional x-rays, there is no radiation exposure with this test.