Pregnancy: are ultrasound scans dangerous for the baby?

Grossesse : est-ce que les échographies sont dangereuses pour le bébé ?

When to have ultrasounds?

For a basic pregnancy with no particular complications, only 3 ultrasounds are necessary and covered by social security. The first ultrasound is called the "dating ultrasound", and takes place between the 11th and 13th week of amenorrhea, i.e. around 3 months into the pregnancy. It lasts 30 minutes and ensures that the fetus is viable, by examining its head, thorax, limbs, abdomen, organs and heart. This ultrasound also verifies that the fetus has no anomalies or malformations. During this first ultrasound, we look for any malformations or fibroids in the ovaries that could have an impact on the pregnancy.

The second ultrasound is called the morphological ultrasound. It is performed between the 22nd and 24th week of amenorrhea. This corresponds to around the 5th month. During this ultrasound, a number of measurements are taken: the diameter and circumference of the head, the brain, the lateral ventricles and the nasal bones. It will also examine all the organs in detail, the speed of the blood in the cord and in the uterine arteries. It is during this ultrasound that the baby's gender can be determined.

The third and final ultrasound is generally performed at around 7 to 8 months, between 31 and 33 weeks of amenorrhea. In this ultrasound, the doctor will measure the baby and check its growth. He also checks all the organs, as well as the limbs, and takes some measurements. Thanks to these measurements, the doctor is able to estimate the baby's full-term weight.

Why are ultrasound scans useful?

Ultrasound scanners use ultrasonic waves. Ultrasound waves are not harmful to health, and have no impact on the body's tissues and organs. Pregnant women undergo ultrasound scans to diagnose and monitor pregnancy, as well as to check for malformations, and so on.

There are 3 types of ultrasound:

- The most widely used ultrasound is 2D, i.e. a single plane. This is the basic ultrasound that is performed in all radiology centers.

- Then, some centers offer 3D ultrasound, i.e. ultrasound in volume, for 3D images.

- And finally, there is 4D ultrasound, in which the notion of temporality is added to volume. This is a dynamic ultrasound in which we can see the baby in 3D over time, since the videos are of the order of 7 images per second.

3D ultrasound and 4D ultrasound are not really useful for diagnosis, but rather for parents. It allows them to see their baby. It has no impact on pregnancy monitoring or malformation diagnosis.

Are 3D and 4D ultrasound scanners dangerous for the baby's health?

3D and 4D ultrasound scans, like 2D scans, also use ultrasound waves. As previously explained, ultrasound waves are not harmful and therefore have no deleterious effects on human body cells, soft tissues or organs. Whether you have a 2D, 3D or 4D ultrasound scan, there will be no negative impact on you or your child.

Do repeated ultrasounds encourage regurgitation in newborns?

There's a common misconception that repeated ultrasound scans cause regurgitation in newborns, but there's no scientifically proven link between repeated ultrasound scans and regurgitation in newborns.

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The information contained in the articles on is general information only. Although reviewed by health professionals, this information is not error-free, does not constitute health advice or consultation, and is not intended to provide a diagnosis or suggest a course of treatment. Under no circumstances may this information be used as a substitute for medical advice or consultation with a healthcare professional. If you have any questions, please consult your doctor.