Ultrasound Examination During Pregnancy is useful for detecting structural abnormalities of the fetus (Fetal Structural Abnormality), especially major structures including the skull, brain tissue, skeleton, limbs, chest cavity, lung tissue, heart, abdominal wall, major internal organs in the abdominal cavity such as liver, kidneys, certain intestinal abnormalities, bladder, etc.
Types of Ultrasound Examinations
- 2D Ultrasound
- 3D Ultrasound
- 4D Ultrasound
2D Ultrasound
This involves sending sound waves and receiving images in a plane or two dimensions, similar to cross-sectional or longitudinal images of an object, resulting in images without the depth that real objects have. It has lower resolution than 3D or 4D ultrasound and cannot capture continuous images or moving objects like 4D ultrasound.
3D Ultrasound
This scans or renders the surface area as if viewing an object or a person, showing the outer surface of the person in a 3D image with width, length, and depth. The probe and processing equipment are more complex, sending sound waves in multiple planes. It shows the surface characteristics, displaying an image resembling the real object’s surface in 3D, but as a still image.
4D Ultrasound Examination
This uses high-frequency sound waves transmitted through moving objects, capturing continuous data over the examination period. It allows real-time viewing of the fetus moving inside the mother’s womb, showing actions, expressions, and postures during the scan, such as yawning, finger movements, turning the face, hearing the baby’s heartbeat, etc. The images are continuous and appear as moving pictures like a movie, unlike 3D ultrasound. This helps clearly study various fetal behaviors.
Additionally, 4D ultrasound images are easy to view for the general public and are very useful for diagnosing abnormalities of external organs such as cleft lip, extra fingers or toes, etc. Allowing parents to see their baby also helps build family bonding starting from when the baby is still in the womb. Doctors can also assess whether the fetus is growing and developing appropriately in the womb, such as:
- Fetal position, umbilical cord, and amount of amniotic fluid around the fetus
- Skull structure and fetal brain
- Arms, legs, hands, feet, and fingers
- Heart and fetal blood circulation
- Spine, stomach, bladder, and kidneys
- Face and various facial organs of the fetus
- Fetal growth rate, head circumference, length, and weight
- And what parents eagerly want to know: the sex of the fetus
However, minor abnormalities may not be detectable by ultrasound at that time and may require waiting until the fetus is larger or after birth for detection. Another advantage of 4D ultrasound is the ability to record the examination images (playable on DVD players and computers). The appropriate gestational age for this type of ultrasound can be at any stage. Obstetricians will schedule ultrasound examinations periodically, with images varying according to the baby’s development.
Ultrasound machines are highly safe and can be used throughout pregnancy without limiting the number of times. There are also reports certified by the U.S. Food and Drug Administration (FDA) stating that ultrasound examinations during pregnancy have no reported adverse effects on the mother or fetus.
