What Is an Anatomy Scan for Your Baby?
The anatomy scan, also known as the 20-week ultrasound or anomaly scan, is a routine part of prenatal care. It is typically performed between 18 and 22 weeks of pregnancy. This non-invasive imaging technique offers a detailed look at the developing fetus, providing information about its growth and health. It allows healthcare providers to assess the baby’s development during this stage of pregnancy.
What the Scan Entails
The anatomy scan uses sound waves to create images of the inside of the body. During the procedure, the expectant parent lies on an exam table, and a sonographer applies a specialized gel to the abdomen. This gel helps the transducer, a handheld device, glide smoothly over the skin and ensures optimal transmission of sound waves.
As the sonographer moves the transducer across the belly, the sound waves bounce off the baby’s internal organs and fluids, generating two-dimensional images on a monitor. The sonographer captures various views and measurements by freezing the screen and making selections. The scan typically takes 45 to 75 minutes, though it can be shorter if the baby is in a cooperative position.
Purpose of the Anatomy Scan
The anatomy scan evaluates the baby’s physical development and detects potential structural differences. Sonographers meticulously examine various parts of the baby, including the head, brain, spine, heart, lungs, kidneys, bladder, arms, and legs. This assessment ensures organs are forming as expected and the baby is growing appropriately.
The scan also involves taking specific measurements, such as head circumference, abdominal circumference, and femur length, to estimate the baby’s weight and track its growth trajectory. Beyond the baby’s anatomy, the sonographer assesses the position and appearance of the placenta, the umbilical cord (checking for blood flow and vessel count), and the amount of amniotic fluid surrounding the baby. These elements are important indicators of the pregnancy’s progression and the baby’s well-being.
The anatomy scan can help identify signs of certain congenital conditions, such as spina bifida, congenital heart defects, and cleft lip. While it is a comprehensive screening tool, it does not detect all possible conditions. If any concerns arise during the scan, further tests or consultations with specialists may be recommended to gain more information.
Preparing for and Understanding the Scan
Preparing for an anatomy scan involves minimal steps. Many providers recommend arriving with a full bladder, as this can improve the clarity of the ultrasound images, though some facilities may prefer an empty bladder for later scans. Wearing comfortable, loose-fitting clothing, especially two-piece outfits, can make the process more convenient since only the abdominal area needs to be exposed.
During the scan, the sonographer focuses on obtaining clear images and measurements, which often means they may not provide detailed commentary. Your healthcare provider will discuss the findings with you either immediately after the scan or at a follow-up appointment. If desired, the anatomy scan is an opportunity to learn the baby’s sex, provided the baby is in a favorable position. If the sonographer is unable to get all necessary views, perhaps due to the baby’s position, a follow-up appointment might be scheduled to complete the assessment.