How to Read a Pregnancy Ultrasound Report: Decoding Common Terminology

Fetal ultrasounds are a standard prenatal screening tool and medical imaging test used to monitor your health and the health of your baby during pregnancy. While pregnancy ultrasounds are a reliable way to track and measure your baby’s progress, reviewing your ultrasound report can be daunting. Pregnancy ultrasound reports often include acronyms and medical terminology that the average person may not recognize and knowing how to read ultrasound numbers and measurements can be intimidating.

If you’re experiencing anxiety waiting to review your ultrasound imaging test results with your OBGYN, family doctor or midwife, this article can help you decode the abbreviated medical language and terms in your report. By understanding the terms in your ultrasound, you can stress less before your appointment and have confident, informed conversations with your healthcare team.

How does a pregnancy ultrasound work?

During your fetal ultrasound examination, a trained technician called a sonographer will use a hand-held device called a transducer to create and capture sound waves. Too high pitched for human ears to hear, those sound waves travel through your body and bounce off different structures in different ways. The ultrasound machine detects and uses these signals to create an image of the position and shape of your growing pregnancy. These captured images are then interpreted by a radiologist.

Main Types of Ultrasound Procedures

There are two main types of ultrasound procedures done during pregnancy:

• Transabdominal scan (TAS): A sonographer will squeeze gel onto your belly and then run the transducer over the surface of your skin to capture the fetal anatomy of your growing baby.
• Transvaginal scan (TVS): A sonographer will insert a lubricated wand into your vagina to capture more detailed images of your uterus, ovaries and fallopian tubes, allowing for a closer look at your pregnancy and determining any early pregnancy complications.

Early in your pregnancy, you’ll likely have both an abdominal ultrasound and transvaginal ultrasound, since the embryo is so small that the transducer successfully captures more details inside the vaginal canal than it can outside the abdomen. From the second trimester onwards, you’ll likely only have abdominal ultrasounds.

How to read a fetal ultrasound report

Here’s an alphabetical list of the most common medical acronyms you’ll encounter when reviewing your pregnancy ultrasound results, with an explanation of each:

• AC (Abdominal circumference): The measurement of the fetus’s abdomen used to assess fetal growth and development.
• AF (Amniotic fluid): A clear liquid that surrounds the fetus during pregnancy. Contained in the amniotic sac, AF helps cushion the fetus, allowing for safe movement and regulating environmental temperature.
• BPD (Biparietal diameter): A standard used to assess fetal growth and development by measuring the distance between two sides of a fetus’ head.
• CPR (Cerebroplacental ratio): An obstetric tool used to measure fetal growth and adverse pregnancy outcomes by assessing cardiac output.
• CRL (Crown-rump length): A measurement of the embryo or fetus from the top of its head to the bottom of its torso used to estimate gestational age.
• EDD (Estimated date of delivery): A calculation to determine the most likely date of spontaneous natural birth.
• EFW (Estimated fetal weight): EFW is a measurement determined by assessing the size and measurements of various parts of a fetus, including the head circumference (HC), abdominal circumference (AC) and femur length (FL).
• FGR (Fetal growth restriction): Is defined as a low fetal weight less than the 10th percentile in weight for gestational age, taking into consideration the growth potential.

Decoding Specific Ultrasound Measurements

What does BPD mean on an ultrasound? Specifically, BPD can help your practitioner determine gestational age when measured between 14 and 20 weeks of pregnancy. In addition, CRL is used to assess age between weeks 6 and 13 of pregnancy, after which other measurements like BPD and head circumference (HC) may be more accurate. Furthermore, AF can be measured using the Amniotic Fluid Index at any time after the 24-week mark of a pregnancy. Regarding timing, CPR is typically measured within 2 weeks of delivery to determine placental sufficiency before delivery. Finally, EDD can be determined by reviewing ovulation and menstruation dates prior to conception or by examining the size of the uterus through a pelvic exam.