General Practice 2022

3D or 4D ultrasound: differences and when to do it

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3D or 4D ultrasound: differences and when to do it
3D or 4D ultrasound: differences and when to do it

3D or 4D ultrasounds can be done during prenatal care between weeks 26 and 29 and are used to see the baby's physical details and assess the presence and also the severity of diseases, not just performed with the purpose of decreasing the parents' curiosity.

The 3D exam shows details of the baby's body, making it possible to see the face and genitals more clearly, while in the 4D exam, in addition to the well-defined features, it is also possible to visualize the movements of the fetus in the mother's belly.

These exams are performed in the same way as conventional ultrasound, without any special preparation. However, it is only recommended not to use moisturizing creams on the belly and to drink plenty of fluids the day before the exam.

Main differences between 3D and 4D ultrasound

The main difference between 3D and 4D ultrasound is that in 4D ultrasound it is possible to capture the baby's movements, but it can make the image a little less clear, while in 3D ultrasound the image is static, without movement, having greater sharpness.

However, these two types of ultrasound allow you to see three-dimensional images that show the baby in detail.

When to do

The best time to do 3D and 4D ultrasounds is between the 26th and 29th week of pregnancy, as the baby is already grown in these weeks and there is still plenty of amniotic fluid in the mother's belly.

Before that period, the fetus is still very small and with little fat under the skin, which makes it difficult to see its features, and after 30 weeks the baby is very large and takes up a lot of space, making it difficult to see your face and your movements.Also see when the baby starts to move.

Illnesses identified by ultrasound

In general, 3D and 4D ultrasounds identify the same diseases as conventional ultrasound and therefore are usually not covered by he alth plans. The main changes detected by ultrasound are:

  • Hare lip, which is a bad formation of the roof of the mouth;
  • Baby's spine defects;
  • Brain malformations such as hydrocephalus or anencephaly;
  • Limb, kidney, heart, lung and intestine malformations;
  • Down Syndrome.

The advantage of 3D or 4D exams is that they allow a better assessment of the severity of the problem, and can be performed after diagnosis with conventional ultrasound. In addition, in most cases, morphological ultrasound is used, which is part of the prenatal exams that must be done to identify diseases and malformations in the baby.Learn more about morphological ultrasound.

When the image is not good

Some situations may interfere with the images generated by the 3D or 4D ultrasound, such as the position of the baby, which may be facing the mother's back, which prevents the doctor from identifying her face, or the fact that of the baby having the limbs or the umbilical cord in front of the face.

Furthermore, the low amount of amniotic fluid or excess fat in the mother's belly can interfere with the image. This is because excess fat makes it difficult for the waves that form the image to pass through the ultrasound device, which makes the images formed not reflect reality or have good resolution.

It is important to remember that the exam starts with a normal ultrasound, as 3D/4D ultrasound is only performed when good images are obtained in the conventional exam.

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