The 20-week scan has been used in prenatal screening for years. This is also known as the structural ultrasound examination (SEO), or an anomaly scan. This is an ultrasound that looks for possible visible abnormalities in the baby.
Last September, as similar ultrasound was introduced in the Netherlands at an earlier stage of pregnancy, in the first trimester around 13 weeks. Hence the name 13-week scan, but it is also called a first-term structural ultrasound examination (ETSEO), comparable to the 20-week scan.
What is the difference with the 20 week scan?
Quite simply put, the difference is the degree of development of the child. At 13 weeks, the baby is still a lot smaller and less developed. However, the sonographer can already see some (often serious) abnormalities. The advantage of this is that there is more time for follow-up exams and making choices.
Important! The 13 week ultrasound does not replace the 20 week ultrasound!
Why should I choose this ultrasound?
The most important thing about this ultrasound is that it is performed much earlier than the 20 week ultrasound. So if a potentially serious abnormality is seen, action can be taken earlier. In case of poor imaging (due to, for example, a high BMI or scar tissue), a vaginal ultrasound is also possible during with the 13 week scan, while at 20 weeks the baby is too big for this.
Why should I NOT choose this ultrasound?
Each ultrasound remains a personal choice, you can simply choose not to have prenatal screening performed. This is important because: your body, your choice! You also want to be able to enjoy your pregnancy undisturbed. The result of the 13-week ultrasound may also be negative or inconclusive. With the latter, you will actually be in a state of unrest early in the pregnancy, while it doesn't necessarily have to be that way. You want this tension as little as possible, because you also want to enjoy this special time.
Combined test; nuchal translucency and serum screening
Previously, the combined test was the most reliable non-invasive way to screen for chromosomal abnormalities. In this test, blood was taken (from the mother) between 9 weeks and 14 weeks, and an ultrasound was done to measure the nuchal translucency between 11 weeks and 14 weeks. Serum markers were examined in the blood. The results indicated whether there was a high or low risk of trisomy 13 (Edwards syndrome), 18 (Patau syndrome) and 21 (Down syndrome). A thickened nuchal translucency can also say something about the risk of other chromosomal abnormalities (including Turner's syndrome) and heart defects.
NIPT and 13 weeks ultrasound
Nowadays, the combined test is no longer performed in many places. In the Netherlands, this has been replaced by the NIPT ('non-invasive prenatal test') and the 13-week ultrasound. The NIPT also requires blood to be taken from the mother, but looks at fetal DNA fragments. This is analyzed and gives results with a high degree of certainty whether the child has a trisomy 13 (Edwards syndrome), 18 (Patau syndrome) or 21 (Down syndrome). This is in contrast to the combined test, in which only an increased or decreased risk can be given. In addition, the NIPT doest not generate a false positive result as much as the combined test. The NIPT can also generate secondary findings (other chromosomal abnormalities in the child, placenta, or in rare cases in the pregnant woman herself).
At the 13-week scan, in addition to assessing possible abnormalities and measuring growth, the nuchal thickness (translucency) is also measured as in the combined test.
Are these tests performed on Curaçao?
The combined test is still offered in some places on Curaçao. Previously, the blood was sent to the Netherlands for analysis, now it goes to the United States. This is reimbursed by the SVB. Do you want to have this performed? Please contact your obstetrician or gynaecologist. The NIPT can be taken at two different laboratories on referral from the gynaecologist, but the costs are for your own account (this can be up to 1600 NAf,-).
The 13 week ultrasound is an option here on the island. This is offered at our practice, but is also not (yet) reimbursed (this costs 200 Naf,-). This ultrasound is a nice way to get some information about the health of your baby at an early stage of pregnancy.
More information about the 13 week scan can be found at https://www.pns.nl/prenatal-and-newborn-screening/prenatal-screening
Do you have any questions about this blog? Feel free to contact us.
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