Many expectant parents wonder about the safety of ultrasounds during pregnancy. An ultrasound, also known as a sonogram, provides images of the developing baby and the mother’s reproductive organs. This routine prenatal test helps healthcare providers monitor fetal health and development. Understanding how this technology works and its safety profile can help address common concerns.
How Ultrasound Works
Ultrasound imaging uses high-frequency sound waves to create real-time pictures of structures inside the body. A transducer emits these sound waves into the body. These waves travel until they encounter boundaries between different tissues, such as fluid and soft tissue or soft tissue and bone. When sound waves hit these boundaries, some reflect back to the transducer as echoes.
The transducer converts these echoes into electrical signals. A computer processes these signals, interpreting the speed, direction, and distance the sound waves traveled to construct a two-dimensional image on a screen. Unlike X-rays, ultrasound does not use ionizing radiation, making it a non-invasive imaging method.
Current Safety Understanding
Diagnostic ultrasound has been used in pregnancy for decades with an excellent safety record. Major health organizations, including the U.S. Food and Drug Administration (FDA) and the American Institute of Ultrasound in Medicine (AIUM), state there are no independently confirmed adverse effects from diagnostic ultrasound when used appropriately. These organizations emphasize that ultrasounds, when performed by trained professionals, are safe for both the mother and the developing fetus.
The guiding principle for ultrasound use is “As Low As Reasonably Achieved” (ALARA). This means exposure should be minimized to the lowest level necessary for diagnostic objectives. Healthcare providers use the lowest possible energy settings and shortest scan times to obtain necessary medical information. This careful approach ensures the benefits of diagnostic information outweigh any theoretical risks.
Exploring Theoretical Effects
While diagnostic ultrasound is generally considered safe, sound waves introduce energy into the body, which can have theoretical biophysical effects. These include tissue heating and mechanical effects, such as the formation of small gas bubbles (cavitation). Thermal Index (TI) and Mechanical Index (MI) values are displayed on ultrasound machines to indicate the potential for these effects, allowing operators to monitor and adjust settings.
Diagnostic ultrasounds operate well below thresholds where these theoretical effects are known to cause harm. The FDA advises against non-medical “keepsake” ultrasounds, especially those for entertainment purposes, as they may involve prolonged exposure or untrained operators. These non-medical uses can exceed recommended exposure limits, highlighting the importance of ultrasounds being performed only when medically necessary and by qualified healthcare providers.
Why Ultrasounds Are Performed
Ultrasounds serve several medical functions during pregnancy, contributing to prenatal care. They confirm pregnancy and determine gestational age, establishing an accurate due date. Ultrasounds also allow healthcare providers to check for multiple pregnancies, such as twins or triplets.
The scans monitor the baby’s growth, movement, and heart rate, ensuring proper development. Providers use ultrasound to examine the placenta’s location and assess amniotic fluid. This imaging can also identify potential complications, such as structural abnormalities, or confirm the baby’s position before birth.