Neck fold measurement

Nicole Wendler holds a PhD in biology in the field of oncology and immunology. As a medical editor, author and proofreader, she works for various publishers, for whom she presents complex and extensive medical issues in a simple, concise and logical manner.

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The measurement of neck folds (neck transparency measurement) in a child in the womb can provide clues to a genetic disorder. However, the crease in the neck is not very meaningful as the sole measured value. The neckfold measurement can only be used in conjunction with other values to assess the risk. Here you can find out everything you need to know about the procedure and significance of the neckfold measurement!

Neck wrinkle measurement - a prenatal diagnostic method

The neck fold measurement (neck transparency measurement, NT measurement) is a method of prenatal diagnosis and part of the first trimester screening. It helps to assess the risk of certain genetic disorders and diseases in the unborn. Your doctor will recommend the examination if you have a high-risk pregnancy and there is an increased risk of child malformations.

The best time for the non-invasive examination is the 10th to 14th week of pregnancy - the neck fold measurement is usually carried out as part of the first ultrasound examination. After the 14th week of pregnancy, the NT measurement is no longer meaningful. The examination does not pose a risk for the expectant mother or for the unborn child.

What is the neck crease?

The neck fold is a collection of fluid (edema, dorsonuchal edema) between the skin and the soft tissue in the neck of the fetus just above the spine. This wrinkle can only be seen on the ultrasound between the 11th and 14th week of pregnancy as a black space. During this time, the child's lymphatic system and kidneys are not yet fully developed, so that fluid builds up at this point. The thickness of the neck fold increases up to the 14th week of pregnancy. After that, the lymphatic system and kidneys of the fetus work and the wrinkle recedes.

With the so-called neck fold measurement or neck transparency measurement (NT measurement, NT screening), this neck fold is measured at its widest point using an ultrasound recording. The ultrasound examination can be carried out through the abdominal wall (abdominal) or through the vagina (vaginal). If the neck fold measurement shows values between 1 and 2.5 millimeters, experts speak of a normal result. From around three millimeters, the neck fold is considered thickened, and above six millimeters as strongly thickened.

A thickened crease in the neck can indicate the following disorders or diseases in the unborn child:

Trisomy 13, Trisomy 18, Trisomy 21 (Down syndrome)
Heart defect
Diaphragmatic hernia
impaired lymphatic drainage
fetal anemia (anemia)
Hypoproteinemia
infection

In some cases, the doctor can detect further clues in the ultrasound of affected children. Sometimes, however, invasive follow-up examinations (amniotic fluid examination, chorionic villus sampling) are also necessary in order to be able to better assess the result. It is at the discretion of the respective doctor as to the size of the neck fold transparency from which he recommends further prenatal examinations.

What is the significance of the NT measurement?

A thickened crease in the neck alone does not mean that your child actually has any of the diseases or chromosomal disorders mentioned. Even together with the other parameters of the first trimester screening, only a probability calculation is possible. In the first trimester screening, the results of the NT measurement, other ultrasound features (such as the width of the nose) as well as the blood test and the individual risk (such as the age of the mother) are included in the evaluation. If the value calculated in this way exceeds a certain limit, the risk of hereditary diseases or chromosomal disorders in the child is increased. Further examinations such as an amniocentesis or a chorionic villus sampling can provide certainty - if you want that.

Neck wrinkle measurement - yes or no?

Does the neckfold measurement make sense or does it just make you feel insecure? Many couples ask themselves this question. Basically, the NT measurement alone is of little significance. If the neck fold is too thick, some parents are immediately concerned, and invasive methods usually have to be followed in order to be able to say more precisely. Sometimes no further abnormalities can be found and a normal fetal chromosome set is present - the child is born healthy, although it originally had a thickened fold in the neck.

Conversely, an inconspicuous finding in the neckfold measurement is not automatically a guarantee for a healthy child - it can still have a genetic disorder or disease.

Be aware that the neckfold measurement can only be used to estimate the risk of a genetic disorder or disease in your child. The reliability of this estimate also depends on the doctor's abilities, the image quality, the time of the examination and the position and size of the child. Even together with the other values of the first trimester screening, the neckfold measurement ultimately only allows a statement to be made about the likelihood of your child having a genetic disorder or disease - a reliable diagnosis is therefore not possible.

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