ETSEO

13-Week Ultrasound

An additional prenatal screening during pregnancy

Since September 1, 2021, pregnant women in the Netherlands are offered an additional ultrasound around week 13 of pregnancy. The goal of this scan is to detect physical abnormalities in the baby at an early stage. It is an extra medical screening alongside the standard 20-week ultrasound. Both are considered official prenatal screening tests.

Part of the IMITAS Research Study

The 13-week ultrasound is part of the IMITAS scientific study. This means that you can only have this scan if you consent to the use of your data for research purposes. The data collected helps researchers evaluate the benefits and limitations of this early scan.

How Does the 13-Week Ultrasound Work?

  • During your intake appointment, your midwife will provide detailed information about this scan.

  • In a counseling session, you will discuss the options and make an informed choice.

  • The scan is performed between 12+3 and 14+3 weeks of pregnancy.

  • The ultrasound lasts about 20 minutes (appointment duration: 30 minutes).

  • The sonographer gives you the results immediately after the scan.

Possible Results of the 13-Week Scan

1️⃣ No signs of abnormalities

  • This is the most common outcome (in about 95 out of 100 pregnancies).

  • No further testing is needed.

2️⃣ Some structures are not clearly visible

  • This does not mean something is wrong.

  • Factors such as the baby’s position or a higher BMI may affect visibility.

  • No follow-up is needed; the baby will be re-evaluated during the 20-week scan.

3️⃣ A possible abnormality is seen

  • You will be offered follow-up testing at Amsterdam UMC (AMC location).

  • Our sonographers are specially trained to perform this screening with great care.

Important Information About the 13-Week Ultrasound

✔ Participation in the IMITAS study is required (with signed consent).
✔ Performed only between 12+3 and 14+3 weeks of pregnancy.
✔ The scan is free of charge.
✔ The baby’s gender is not determined during this scan.
✔ You will receive the results immediately after the scan.
✔ If not all structures are visible, this does not require follow-up—your baby will be reassessed at the 20-week scan.

Prefer Not to Have the 13-Week Scan?

Even if you choose not to have the scan, you can still participate in the IMITAS study. Your reasons for declining are also valuable for the research.

More Information

📌 PNS – Prenatal Screening
📌 RIVM – Dutch National Institute for Public Health

The official brochure about the 13-week ultrasound (ETSEO) is available in Dutch, English, Turkish, Polish, and Arabic.