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  • 03.01.2019
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week pregnancy dating scan - NHS

Nuchal Translucency Screening in Pregnancy - Why NT scan is done during pregnancy?

The presence of a thickened NT, even if the karyotype is normal, can be associated with structural abnormalities. Hereby we present six cases of chromosomally normal fetuses with an increased NT thickness in the first trimester, a normal karyotype and normal follow-up scans, who had a good prognosis for a normal early childhood. This report may help increase the confidence of couples who are reluctant to terminate the pregnancy. Fetal nuchal translucency NT refers to the sonographic appearance of subcutaneous edema in the fetal neck measured according to the fetal medicine foundation FMF guidelines. NT is defined as the maximal thickness of the sonolucent zone fluid accumulation between the inner aspect of the fetal skin and the outer aspect of the soft tissue overlying the cervical spine or the occipital bone Figure 1. To avoid false negative or positive results, the fetus should be in a neutral position, with the head in line with the spine.

NT focuses on a small, clear space at the back of a growing baby's neck called the nuchal fold. Experts have found that this spot tends to accumulate fluid and, as a result, expands in size in babies who have genetic abnormalities like Down syndrome caused by an extra copy of chromosome 21, one of the 23 pairs of chromosomes that contain a person's genetic codetrisomy 18 an extra copy of chromosome 18 and trisomy 13 an extra number 13 chromosome.

Because NT screening has a relatively high rate of error on its own, your practitioner may offer what's known as a combined screening, where NT ultrasound results are combined with one or two blood tests that measure and compare your levels of hCG and PAPP-A pregnancy associated plasma protein Atwo hormones produced by the fetus and passed into your bloodstream.

Dating scan nt measurement

NT results by themselves have an accuracy rate of just 70 to 75 percent. That means that the test misses 25 to 30 percent of babies with Down syndrome or other chromosome disorders.

Pairing the results of the first trimester combined screening with the results of the NT screening can improve the accuracy of detection for Down syndrome to between 83 and 92 percent. The results of an NT screen can also be combined with two other types of blood screenings, the quad screen known as an integrated screening or noninvasive prenatal testing NIPTto provide a more accurate risk assessment.

If your NT or combined screening results indicate that your baby may be at an increased risk for having a genetic abnormality, your practitioner will likely offer a diagnostic test like chorionic villus sampling CVS or amniocentesis. Because increased NT measurements are also associated with fetal heart defects, your practitioner might also suggest a fetal echocardiogram at around 20 weeks to screen for heart defects.

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Increased NT measurements may also be linked to a very slightly higher risk of preterm birthso you may be monitored for that as well. Keep in mind that the nuchal translucency and the associated bloodwork don't directly test for chromosomal problems, nor do they diagnose a specific condition.

Rather, the results merely provide you with your baby's statistical likelihood of having a problem. An abnormal result on the nuchal translucency or combined screening test definitely doesn't mean that your baby has a chromosomal abnormality, only that he or she has an increased risk of having one making follow-up diagnostic testing advisable.

In fact, most women who have an abnormal result on their screening test go on to have a perfectly normal, healthy child. At the same time, a normal result is not a guarantee that your baby is normal, but it does mean that it's very unlikely your baby a chromosomal defect.

The educational health content on What To Expect is reviewed by our team of experts to be up-to-date and in line with the latest evidence-based medical information and accepted health guidelines, including the medically reviewed What to Expect books by Heidi Murkoff.

Nuchal Translucency Screening in Pregnancy - Why NT scan is done during pregnancy?

This site complies with the HONcode standard for trustworthy health information. This educational content is not medical or diagnostic advice.

Use of this site is subject to our terms of use and privacy policy. Getting Pregnant. First Year. Baby Products. Nuchal Translucency Screening.

A nuchal translucency scan is part of the ultrasound scan that may give an indication alone, or it might be able to be done while you're having your dating scan. the nuchal translucency measurement of your baby, the gestational age of the.

Reviewed April 30, Learn more about NT screening, an early, noninvasive option that can screen for chromosomal disorders. Who should get a nuchal translucency screening?

A nuchal scan or nuchal translucency (NT) scan/procedure is a sonographic prenatal screening There are two distinct measurements the nuchal translucency, which is measured earlier in pregnancy at the end of the first The scan may also help confirm both the accuracy of the pregnancy dates and the fetal viability. Nuchal translucency (NT) is the sonographic appearance of a collection of fluid Screening by NT can detect about 80% of fetuses with trisomy 21 and other. A nuchal translucency scan (NT scan) is an ultrasound screening test for To date your pregnancy accurately, the sonographer will measure your baby from the.

When a nuchal translucency screening is done NT screening must be performed between 11 and 13 weeks of pregnancy. How an NT screening is done An NT is a special type of ultrasound using a highly sensitive ultrasound machine.

fetus is alive, accurate dating of the pregnancy, early diagnosis of major fetal . age, ultrasound examination for measurement of fetal nuchal translucency and. A sonographer will first measure your baby from crown to rump to ensure that the fetal age is accurate. Then he or she will locate the nuchal. her routine dating scan, the scan should be performed for anatomy A nuchal translucency (NT) measurement greater than or equal to.

The term translucency is used, irrespective of whether it is septated or not and whether it is confined to the neck or envelopes the whole fetus. In fetuses with chromosomal abnormalities, cardiac defects and many genetic syndromes the NT thickness is increased. The Fetal Medicine Foundation FMF has introduced a process of comprehensive training, support and audit for the proper implementation of early screening for chromosomal abnormalities.

Nuchal translucency (NT) measurements in the first trimester screening between 11 and 14 weeks' gestation are regarded as a clear marker for. Your baby's chances of having a chromosomal abnormality are determined by the nuchal translucency measurement, your age, your baby's gestational age and . The nuchal translucency measurement can be taken during the dating scan. If you have agreed to have screening for Down's syndrome, the dating scan and the.

The FMF advocates that effective screening requires:. The requirements for obtaining the FMF certificate of competence in the nuchal translucency NT scan are:. If you want to visit your own FMF page please click here.

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