Fetal Abdominal Circumference via Ultrasound Measurement

Why Is This Test Done?

Your healthcare provider may order this test during prenatal visits to monitor your baby’s growth. It’s often used at around 18–24 weeks of pregnancy to confirm the baby is developing normally. In some cases, it may be repeated later in pregnancy to check for growth patterns or potential issues like intrauterine growth restriction.

How Is the Test Performed?

You’ll lie on your back on an exam table. A gel is applied to your abdomen, and a transducer (a device that sends and receives sound waves) is placed on your skin. The ultrasound machine captures images of your baby’s abdomen, and the circumference is measured by a technician or doctor.

What Does the Result Mean?

The result compares your baby’s abdominal size to expected growth curves for your gestational age. A measurement that falls outside the typical range may signal further evaluation, such as additional ultrasounds or discussions with your provider about potential risks.

When Might You Need Follow-Up?

If your fetal abdominal circumference is lower than expected, your provider may recommend closer monitoring, including more frequent ultrasounds or additional tests to check for conditions like low amniotic fluid or growth delays. If it’s higher, they may also investigate further to rule out other factors.