The Safety and Uses of Fetal Ultrasound

Is Ultrasound Harmful to the Fetus?
Currently, there is no scientific evidence to suggest that ultrasound poses any harm to the developing fetus. Ultrasound employs high-frequency sound waves that are beyond the range of human hearing, making them entirely safe for prenatal diagnostic purposes.

1. Applications and Techniques of Fetal Ultrasound

Fetal ultrasound serves multiple purposes and employs various techniques, including:

1.1. Routine Black and White Ultrasound

Routine black and white ultrasound is used to visualize different fetal structures, distinguishing between them based on the varying intensity of the reflections. This enables the identification of organs such as the liver, kidneys, and intestines.

1.2. Color Doppler Ultrasound

Color Doppler ultrasound is utilized to assess blood flow, flow direction, and velocity in the fetal heart and blood vessels. It aids in detecting issues like mitral and tricuspid valve regurgitation, measuring blood flow through key arteries, and assessing the health of the fetus in cases of suspected small size or malnutrition.

1.3. 3D - 4D Fetal Ultrasound

3D - 4D ultrasound technology creates three-dimensional or real-time four-dimensional images by transmitting ultrasound waves at various angles and processing the returned waves with computer assistance. This technique is often used to examine detailed structures like the fetal face and dynamic elements such as the fetal heart.

2. Four Crucial Stages for Fetal Ultrasound

Fetal ultrasound is performed at specific stages of pregnancy for various purposes:

• Weeks 6 - 10: Determining fetal location in the uterus, identifying the number of fetuses (single or twin), and confirming fetal viability by assessing the presence of a heartbeat.
• Weeks 11 - 13: Measuring the nuchal translucency to predict chromosomal abnormalities that could lead to conditions like Down's syndrome, heart malformations, or limb deformities.
• Weeks 22 - 24: Comprehensive examination of fetal development, including the spine, skull, brain, heart, lungs, kidneys, and limbs. This stage also allows for the detection of cleft lip, cleft palate, and internal organ malformations.
• Weeks 30 - 32: Assessment of arteries, heart, brain structures, umbilical cord functionality, placental position, and the condition of amniotic fluid.

3. Safety of Fetal Ultrasound

There is currently no scientific evidence to suggest that fetal ultrasound poses any risk to the baby. As previously mentioned, the high-frequency sound waves used in ultrasound are considered safe. However, it is advisable not to overuse Doppler ultrasound, especially during the first 1-2 months of pregnancy when important organs are forming, as excessive exposure can have a thermal effect.

4. Limitations of Fetal Ultrasound

Fetal ultrasound is primarily an imaging tool that focuses on the morphological structure of the fetus. It cannot detect all abnormalities, particularly chromosomal abnormalities or gene mutations. For example, it may only detect 50% of Down syndrome cases due to observable manifestations on ultrasound, while certain fetal central nervous system and cardiovascular abnormalities require magnetic resonance imaging (MRI) for accurate diagnosis, such as cerebral hemorrhage, cerebral smoothness, white matter abnormalities, and brain gray matter issues.