Ultrasound examination during pregnancy

Synonyms in a broader sense

Ultrasound examination, sonography, sonography

Ultrasound as a preventive examination

The examination using ultrasound has become an indispensable part of prenatal care today. Every pregnant woman should be accompanied by a gynecologist during pregnancy, during which at least three preventive examinations should take place, in which an ultrasound is carried out: The first appointment should be between the 9th and 12th, the second between the 19th and 22nd. and the third take place between the 29th and 32nd week of pregnancy.

Read more on the topic: Ultrasound of the abdomen

With the help of the ultrasound, the doctor can obtain important information about the existence of a pregnancy, the development of the unborn child, its health and location and the expected due date. These three ultrasound examinations (also: ultrasound screenings) are legally guaranteed to a pregnant woman, which is why the Health insurance are obliged to bear the costs of these examinations. However, they will only take over further examinations if the doctor discovers irregularities in one of the standard examinations. Ultrasound is such a practical way to monitor pregnancy because it is unlike other imaging techniques (such as roentgen or Computed Tomography) is not associated with radiation exposure and therefore does not pose a risk to the expectant mother or her unborn baby according to current knowledge. And yet, with the help of the three ultrasound examinations, the most common disorders can be uncovered with a relatively high degree of certainty, although a 100% hit rate for the detection of diseases or malformations can of course never be guaranteed.

First ultrasound examination

The first ultrasound scan is a special event for many parents as it is the first time they see their baby, who is growing in the womb. As a rule, this first ultrasound is performed vaginally (Vaginal or transvaginal sonography). To do this, the patient lies on her back, and then an elongated ultrasound probe is pulled over a plastic cover that resembles a condom. The contact gel that is necessary to obtain a clear image is applied to this plastic coating. Then the ultrasound probe is inserted through the patient's vagina. Even if this examination is generally not painful, many women still find it uncomfortable. Compared to abdominal ultrasound, however, this method produces images of much better quality.

During this initial examination, the pregnancy is confirmed and it is checked whether it is a normal pregnancy or an abdominal cavity or ectopic pregnancy. In addition, it can be seen here whether there is possibly a multiple pregnancy. Furthermore, the doctor pays attention to whether movements can be seen that indicate the child's vitality, whether the development up to this point is age-appropriate and whether the heartbeat is regular. Even at this early stage, some abnormalities can sometimes be recognized, for example if the child has Down syndrome (trisomy 21).

Another part of the first ultrasound examination is the determination of the expected due date. To do this, the gynecologist needs the date of the woman's last period and also measures three values: the crown-rump length (SSL) of the fetus, the biparietal diameter (the distance between the two temples of the unborn child, BPD) and the fruit sac diameter (FD) .

If the information given by the woman is correct and the examination is carried out in a timely manner (later in pregnancy, the meaningfulness of the measured values ​​is much lower), the due date can be determined with a relatively high degree of accuracy.

Second and third examinations

During the second and third preventive examinations, the ultrasound is usually carried out on the abdomen, i.e. over the abdominal wall. To do this, the woman lies on her back again, but this time the gel is applied directly to the stomach and the ultrasound probe is placed here. The second ultrasound scan is probably the most important of the three and usually takes the longest, in quite a few cases up to three quarters of an hour. In the meantime, much more details can be recognized by ultrasound, for example the umbilical cord, the placenta (placenta) and the cervix. As a result, the doctor can again (and more precisely) examine the presence of a multiple pregnancy, cardiac activity, development and the body contour of the unborn child. In addition, the amount of amniotic fluid, the location of the placenta and a larger number of malformations can already be recognized at this stage.
If there are any abnormalities or unclear findings during this examination, either further ultrasound examinations can be arranged for control or further methods of prenatal diagnosis (PND) can be used. These include, among other things, the chorionic villus sampling, the umbilical cord puncture, the examination of the amniotic fluid (Amniocentesis), neck fold measurement or fetoscopy. Indications for this would be, for example, suspected intrauterine fetal death, incorrect placenta or diseases of the mother. It often makes sense to go to a special diagnostic center for such examinations, as a great deal of specialist knowledge is sometimes required to correctly assess the findings.

The third (and usually the last) ultrasound examination is used again to check the child's healthy development based on the measurements that have already been carried out. It is also important that the position of the unborn child is determined on this date in order to make special arrangements for the upcoming birth if necessary. If the child's position is unfavorable, this gives rise to further ultrasound examinations from the 36th week of pregnancy.

Further investigations

It is important that all results from all three preventive examinations are recorded in the maternity record in order to ensure a good follow-up, even if the following examinations are carried out by another doctor or in the hospital.

A special form of ultrasound is the so-called Doppler sonography. This examination can be used to assess the blood flow in vessels (especially the umbilical cord vessels, the placenta or directly on the heart) more precisely and thus obtain information about the oxygen supply to the baby. There is also the 3D ultrasound examination, which is one of the latest developments in antenatal care. With the help of the resulting three-dimensional image, certain malformations (such as cleft lip and palate or open back) can be diagnosed with greater certainty. However, these two special examination methods should only be carried out if medically necessary.

Controlling the blood flow in the placenta can provide information about other placenta diseases. In this context, calcifications in the placenta can be diagnosed. Read our article on this: Calcified placenta

Read more on the topic: Doppler sonography