20-weeks scan

What is the 20-weeks scan?
The 20-week echo is also called the routine ultrasonographic test (SEO in Dutch). Fortunately, the vast majority of children are born healthy. 

Prenatal screening can help set your mind at ease about your child’s health. However, it can also be a source of uncertainty and force you to face some difficult decisions. You are free to choose whether or not you want to undergo testing and whether you want follow-up testing if the results are unfavourable. You can decide to break off testing at any time.

This 20 week screening test examines the physical abnormalities of your unborn child. This ultrasound thoroughly examines the development of the child’s vital organs. Furthermore, it looks into the growth of the child and if there is sufficient amniotic fluid. Examples of abnormalities that might can be detected during this ultrasound include:

•   An open back/ spina bifida;

•   An open skull;

•   Waterhead/ hydrocephalus;

•   Heart diseases;

•   Rupture or hole in the diaphragm;

•   Rupture or hole in the abdominal wall;

•   Lack of or deviation of the kidneys;

•   Lack of or deviation of bones;

•   Deviations of arms or legs.

The 20-week echo is not intended to determine the sex of your child, but we can (double) check it if you desire. 

The examination

The 20-week echo is just like the other echoes during your pregnancy. We also ask you if you want to have your cervix measured with a internal ultrasound. A short cervix (<30 mm) might gives a higher change for preterm labour so we will sent you to the UMC, location VUmc if this is the case. The total time of the 20 weeks scan is approximately 45 minutes.

The time

The 20-week echo is conducted when you’re about 20 weeks pregnant. The ideal period is between 19 and 20 weeks.

The results

The sonographer will inform you about the results should they be troubling or if they doubt the outcome. You will hear this directly after the echo is done. Deviating results means that you’ll be examined further. The sonographer will advise you on the follow-up examination and discuss this with your midwife. Usually this results in an extensive sonographic examination. This is called an advanced ultrasound examination (GUO in Dutch) and it's done at the University Medical Center, UMC location VUmc in Amsterdam.

In some cases we sent for a second opinion, it will appear that there is nothing to worry about. For those cases where health problems are detected, a follow-up study is of great importance.

However it must be said that not all diseases are visible. In case of reference to follow-up examinations you can always contact your midwifes at Femme-Amsterdam for advice and support.

How reliable is the 20-week echo?

The chance of discovering abnormalities depends on the the type of abnormality.
For example, the chance that an open back/ spina bifida is discovered is approximately 90 out of 100. The chances of discovering heart diseases at 20 weeks are 25 to 50 out of 100, depending on the severity of the disease. The 20-week ultrasound does not give you a guarantee for a healthy child. Not all disorders can be noticed during the ultrasound.

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