Abdominal ultrasound of pregnant uterus, first trimester

Procedure Information

What is Abdominal Ultrasound for Pregnancy (Fetal Ultrasound)?

Abdominal Ultrasound for Pregnancy, also known as Fetal Ultrasound, is used to produce high-quality images of your baby inside the uterus. It is an imaging technique that uses sound waves to produce detailed images. The first ultrasound is usually done during the first trimester to confirm the pregnancy and estimate how long you have been pregnant. There are two main types of fetal ultrasound exams: transvaginal or transabdominal.

Transabdominal ultrasound is done by moving a transducer over your abdomen. There are various other types of transabdominal ultrasounds including 3D ultrasound, fetal echocardiography, and doppler ultrasound.

Why would I get a fetal ultrasound?

A first-trimester ultrasound examination is done to evaluate the location of the pregnancy, size of the fetus, estimate how low you have been pregnant, and the number of fetuses. Fetal anatomy and other features are evaluated in the second or third trimester by ultrasound.

Fetal ultrasound can help your doctor to:

• Investigate complications.
• Study the placenta and amniotic fluid levels.
• Recognize birth defects.
• Carry out other prenatal tests.
• Find out the feta position before delivery.

What happens during a fetal ultrasound?

You may be asked to avoid urinating or to drink a certain amount of fluid before the procedure. During an ultrasound, you will be asked to lie on a padded examining table. Then a small amount of water-soluble gel is applied over your abdomen. The gel doesn’t stain clothes or harm your skin.

Your doctor will gently apply a small device, called a transducer, against your abdomen. The transducer sends high-frequency sound waves, which reflect off internal structures, including your baby. Your doctor will examine your baby's anatomy and will print certain images to document important structures. 

What to expect after the procedure?

There is no discomfort during or after the test. If you had a full bladder during the exam, you can urinate after the exam. There are no special precautions required unless your doctor has another opinion.

Conclusion

Your doctor will discuss your results with you. If the pregnancy remains uncomplicated, the next ultrasound can be offered during the second trimester, when the anatomic features of your baby are visible enough. If your doctor suspects a problem, additional imaging tests and a follow-up ultrasound might be recommended.

Citations

Mayo Clinic: Fetal ultrasound