The Level 2 ultrasound scan, often called the detailed anatomical scan or anomaly scan, uses high-frequency sound waves to create a detailed picture of the developing fetus, placenta, and surrounding structures. Performed during the second trimester of pregnancy, this non-invasive imaging procedure serves as a comprehensive health assessment for the baby. It detects potential structural variations or developmental concerns early in the pregnancy, providing expectant parents and healthcare providers with crucial information.
Defining the Detailed Anatomical Scan
The Level 2 ultrasound is a specialized examination typically scheduled between 18 and 22 weeks of gestation. This timing is chosen because the fetal organs and structures are sufficiently formed and large enough to be clearly visualized and measured. The primary purpose of this scan is to evaluate the detailed anatomy of the fetus for any signs of congenital malformations or growth abnormalities.
This procedure differs from a routine Level 1 ultrasound, such as a dating scan. While the Level 1 scan confirms viability and estimates gestational age, the Level 2 scan requires specialized training and advanced equipment to conduct a systematic, head-to-toe survey of the baby’s internal and external structures. The Level 2 examination is a standard part of prenatal care, moving beyond simple confirmation to detailed structural analysis.
Preparing for the Appointment
Preparing for this detailed appointment involves steps to ensure the best possible image quality for the sonographer. It is recommended to wear comfortable, two-piece clothing, as this allows the abdomen to be easily exposed for the transabdominal approach. The transabdominal approach requires a layer of gel to be applied directly to the skin, and two-piece outfits simplify this process.
While older ultrasound techniques often required a full bladder, the need for this is now less strict, though some clinics may still request it. Being well-hydrated before the appointment can improve the clarity of the amniotic fluid and surrounding tissues. The appointment is a longer process than a quick dating scan, often lasting between 30 and 60 minutes, depending on the baby’s position and cooperation.
The In-Depth Examination Process
The core of the Level 2 scan is a methodical, organ-by-organ assessment, which begins with a series of precise measurements known as fetal biometry. The sonographer will capture specific dimensions, including the biparietal diameter and head circumference, which measure the fetal skull, and the abdominal circumference. The length of the femur, the thigh bone, is also measured to assess overall growth and estimate the fetal weight, ensuring the baby is growing appropriately for its gestational age.
Structural Assessment
A comprehensive look at the fetal brain is performed next, focusing on structures like the cerebellum and the lateral ventricles, the fluid-filled spaces within the brain. The integrity of the spine is examined along its entire length, viewing the vertebrae in both longitudinal and transverse planes to rule out conditions like spina bifida. The sonographer also assesses the face, checking the profile, the orbits of the eyes, and the structure of the lips and palate for complete formation.
Organ Function and Circulation
One of the most complex parts of the examination involves the fetal heart, where the sonographer captures views of the four chambers, the major vessels leaving the heart, and the rhythmic flow of blood. This assessment ensures the heart’s structure is fully developed and functioning correctly. The abdomen is then examined to confirm the presence and proper placement of the stomach bubble, which indicates the baby is swallowing amniotic fluid. The two kidneys and bladder are also checked, confirming the urinary tract is working.
Placenta and Limbs
Further checks are made on the umbilical cord, verifying it contains the standard two arteries and one vein, and observing its insertion point into the fetal abdomen. The limbs are reviewed, counting the visible bones in the arms and legs and attempting to visualize the digits on the hands and feet. The sonographer also evaluates the placenta’s location, noting if it is near or covering the cervix, a condition called placenta previa, and measures the volume of amniotic fluid surrounding the baby. Throughout this process, the sonographer will often need the parent to shift positions to encourage the fetus to move and allow for clear views.
Understanding Scan Results and Next Steps
The results of the detailed anatomical scan are typically communicated to the parents immediately following the procedure, or shortly thereafter, by the sonographer or a supervising physician. In the majority of cases, the findings are reassuring, confirming normal growth and development across all the examined structures. A standard, normal report allows the pregnancy to continue with routine prenatal monitoring.
When the scan reveals an unexpected finding or a structural variation, the healthcare team will discuss the implications and potential next steps. An “abnormal” finding can range from a minor variation, sometimes referred to as a soft marker, to a more significant structural anomaly. If a concern is identified, the next step often involves a referral to a maternal-fetal medicine specialist for further consultation and evaluation.
The specialist may recommend a Level 3 scan or a fetal echocardiogram if a heart issue is suspected. Further diagnostic testing, such as amniocentesis, may also be offered to clarify the finding, particularly if a chromosomal issue is suspected. The communication focuses on providing a clear understanding of the finding and outlining all available options for care and management moving forward.