The anatomy scan, also known as the Level 2 ultrasound or mid-pregnancy scan, is a comprehensive, non-invasive imaging procedure used to evaluate the developing fetus. This routine test provides a thorough look at the baby’s anatomy, the placenta, and the surrounding environment within the uterus. The purpose is to ensure the pregnancy is progressing as expected and to identify potential variations that may require follow-up care.
When the Scan Occurs and How to Prepare
The anatomy scan usually occurs between 18 and 22 weeks of gestation. This timing is chosen to maximize visibility and diagnostic detail because the fetus is large enough for internal structures to be clearly visualized and measured. Having the scan mid-pregnancy also allows time for specialized testing or consultations if a finding requires closer attention.
The appointment typically lasts between 30 and 60 minutes to allow the technician sufficient time to capture detailed images and measurements. Preparation is minimal but may involve arriving with a partially full bladder, which can help elevate the uterus for a clearer view. Some providers also suggest having a light snack beforehand, as the resulting fetal movement can help the technician obtain all the required angles.
What Specific Anatomy is Examined
The anatomy scan involves a meticulous, head-to-toe survey of the fetus to confirm that all major body systems are developing normally. A primary focus is on fetal growth, which involves taking biometric measurements to estimate size and weight. These measurements include the head circumference, the abdominal circumference, and the length of the femur bone.
The examination of the nervous system includes a detailed look at the brain structures, ensuring the cerebellum and ventricles are correctly formed. The spine is also carefully assessed in both cross-section and longitudinal views to confirm proper alignment of the vertebrae and complete skin coverage of the spinal cord. The technician also focuses on the four chambers of the heart, checking the integrity of the valves and verifying the correct arrangement of the major blood vessels.
The abdominal organs are systematically checked, confirming that the stomach is present and filled with fluid, indicating the fetus is swallowing. The kidneys and bladder are also identified and assessed for proper structure. The technician will examine the limbs, counting the fingers and toes, and confirming the length and symmetry of the arms and legs.
The scan also assesses the support structures of the pregnancy, including the location of the placenta, ensuring it is not covering the cervix. The umbilical cord is checked to confirm it contains two arteries and one vein. The volume of amniotic fluid is measured, as abnormal levels can indicate other issues. If the fetus is in a cooperative position, the technician can often confirm the sex, if the parents wish to know.
Interpreting Results and Next Steps
Following the comprehensive scan, the images and measurements are reviewed by a physician, such as a maternal-fetal medicine specialist or radiologist. Most anatomy scans yield reassuring results, confirming typical growth and development. The results are then shared with the expectant parents, usually by their healthcare provider at a follow-up appointment.
If the scan reveals a variation, it does not automatically mean a serious problem exists; sometimes, the fetus’s position prevents a clear view, necessitating a repeat scan in a few weeks. Other times, the scan may identify “soft markers,” which are minor structural findings that slightly increase the statistical risk for a chromosomal condition. These markers, such as a bright spot in the heart or a small cyst in the brain, frequently resolve on their own and are often benign variations.
If a more significant structural finding is identified, the medical team will outline the path forward, which may involve further diagnostic testing. This could include a specialized fetal echocardiogram for a closer look at the heart, genetic counseling, or a consultation with a pediatric specialist. Early detection allows the care team to create an informed plan for monitoring the remainder of the pregnancy and coordinating specialized care the baby may need after birth.