Timing

• 11th - 13th week of pregnancy

Purpose

• Measure nuchal translucency (NT) (as part of the 1st screen or sequential screen)
• Confirm multiple pregnancy
• Confirm baby's gestational age and corresponding due date
• Scan for major abnormalities

Description

This scan is carried out from 11 weeks to 13 weeks and six days. The scan is usually performed transabdominally but in a few cases it may be necessary to do the examination transvaginally.

Nuchal translucency (NT) measurement

Nuchal translucensy (NT) is the clear space in the tissue of your developing baby's neck. An NT measurement can help your healthcare practitioner assess your baby's risk of having down syndrome and some other chromosomal abnormalities as well as major congenital heart problems.

Scanning for major abnormalities

Major abnormalities may be visible at this gestation. We will check whether your baby has all its limbs, that the head and brain appear to be developing normally, that the baby has a visible stomach and bladder and the umbilical cord is inserted correctly. From 12 weeks the spine can usually be seen clearly enough to rule out major cases of spina bifida. All of this information provides important reassurance. A more thorough evaluation of fetal anatomy will be done at 20-22 weeks gestation.

Genetic counseling about your results and options

Your NT measurement cannot be used alone to calculate the risk that your baby has down syndrome or another genetic abnormality. We encourage patients to make a same-day appointment with our genetic counselors where they will explain the NT test and how it may fit with other screening and diagnostic tests to calculate your risks and/or confirm your baby's condition.

Counseling for any indicator of concern

If there is any indication of a problem or abnormality, we will discuss the results with you carefully. We can help you understand what the results mean as well as what diagnostic and screening tests might be helpful for you and your pregnancy.