Diagnostics and volumetric visualization together
The combined option combines two tasks that are usually solved in different visits. First, the doctor performs a full screening protocol: fetometry, sequential examination of the fetal anatomy, assessment of the placenta, amniotic fluid and cervix, and, if necessary, Doppler ultrasound. This is the diagnostic part; based on its results, an official protocol is filled out.
After completing the mandatory program, the volumetric mode is turned on. Since the doctor already knows exactly the position of the fetus and the quality of visualization, less time is spent on constructing a three-dimensional image, and the likelihood of getting a successful shot is higher. Parents receive pictures and video recordings without having to come to a separate appointment.
This format is also convenient because volumetric reconstruction is immediately used for its intended purpose: if during an anatomical examination there is a suspicion of an anomaly of the face, hand or spine, the doctor immediately clarifies it in 3D - this often allows either to remove the suspicion or to describe the defect much more accurately than on a flat section.
Why are planned studies needed?
Ultrasound is the main tool for monitoring pregnancy. It confirms that the fetus is alive and developing on time, shows the number of fetuses, the position of the placenta, the volume of amniotic fluid and the condition of the cervix. Most serious malformations are detected by ultrasound, and at a time when it is still possible to make an informed decision.
There are usually three planned examinations during pregnancy - one in each trimester, in strictly defined windows. Outside of these periods, some measurements lose diagnostic value: for example, the thickness of the collar space can be correctly assessed only from the 11th to the 13th week plus 6 days.
Safety of ultrasound during pregnancy
Ultrasound is not ionizing radiation: it does not accumulate in tissues and does not have a radiation dose, unlike X-rays and computed tomography. Over decades of use, no data have been obtained on the harmful effects of diagnostic ultrasound on fetal development.
In this case, the principle of reasonable sufficiency applies: the study is performed according to indications and in the optimal time frame, and the power and exposure time are kept at the minimum required level. This applies separately to the Doppler and 3D/4D modes - they are used consciously, and not “just in case” at each visit.
What affects image quality
The clarity of the picture depends on the age, position of the fetus, the thickness of the anterior abdominal wall, the amount of amniotic fluid and the presence of a scar on the uterus. If the fetus turns its back to the sensor or covers its face with its hands, some structures cannot be examined.
In such cases, the doctor may ask you to walk, change your body position, or come back in a few days. This is not a sign of pathology, but a common technical situation, especially common during 3D/4D examination.