Nuchal translucency scan in 1st trimester

Screening for Down’s syndrome and other fetal defects by nuchal scan at 12 –14 gestational weeks

This scan is carried out from 12 to 14 week. The scan is usually performed transabdominally, only in a few cases it may be necessary to do the examination transvaginally.
The main aim of this scan is to estimate the risk of Down’s syndrome and other most frequent chromosomal defects. We also take this opportunity to do additional examinations.

During the nuchal scan at 12-14 weeks we examine you for:

• Placental position and amount of amniotic fluid
• Gestational age and the expected date of delivery by measurement of the size of the fetus (CRL- crown-rump-length). This is particularly relevant for women who cannot recall the date of their last period, have an irregular menstrual cycle, or who have conceived whilst breastfeeding or soon after stopping the pill.
• The individual risks of Down’s syndrome and other frequent chromosomal abnormalities.
This is calculated by taking into account the maternal and gestational age, measurement of the levels of two hormones in maternal blood and the scan findings of nuchal translucency thickness, nasal bone, blood flow across the tricuspid valve in fetal heart and ductus venosus, fetal heart rate and fetal structural defects.
• Presence of major structural abnormalities. About 50% of major structural abnormalities may be detected at this gestation, however a 20-week anomaly scan is essential.
• The risk of development of pregnancy complications, respectively pre-eclampsia and fetal growth restriction. The risk is calculated by combination of several maternal parameters: obstetrics and personal history, blood pressure, measurement of the level of the hormone PAPP-A (ev. also PlGF) in the blood and blood flow in uterine arteries.

During the scan, we will keep you informed about the parts of fetal anatomy displayed on the screen. If you wish to see the real image of your future baby, you can ask us to add the 3D-4D scan. We will be happy to do this imaging option for you.

At the end of the scan we will calculate your individual risk for the most frequent fetal chromosomal defects and the risk of pre-eclampsia and fetal growth restriction.

After the scan, we counsell you through the significance of the risks of defects and the various options for further testing. If you decide to opt for invasive testing, we offer to perform this, often on the day of your scan. If you decide to have alternate methods for reassessment of the risk of frequent chromosomal defects (NIPT, genetic ultrasound), we would be happy to offer these tests to you at our centre.

The complete examination, which includes the counselling, takes around 45 minutes and you are welcome to bring your partner or someone close to accompany you through the process. From us, you will receive two printed images of your baby and a detailed report with the results will be sent to you by email within a week.

Further recommended scans: