Nuchal Lucency Screening

Nuchal lucency screening, a careful ultrasound that looks for the thickening of the back of the neck of fetuses between 11 and 13 weeks, is an exciting advance in prenatal diagnosis. Nuchal lucency screening involves an ultrasound done be a qualified radiologists with advanced ultrasound equipment, to measure the thickness in the back of the neck of early pregnancies. Thickening in the neck or the absence of a nasal bone are features that place the pregnancy at added risk for chromosomal abnormalities such as Down’s Syndrome.

Ultrasound of Normal Nuchal Lucency ThickeningNuchal luncency testing is noninvasive and therefore very safe. Because the test can be done without the risks of a needle puncture to remove amniotic fluid with amniocentesis, and because the results can be obtained weeks before amniocentesis (16-17 weeks), many of the fears associated with prenatal genetic testing can be alleviated.

Use of the test may lead to less use of amniocentesis for the diagnosis of chromosomal abnormalities. Genetic testing has been traditionally offered only to those patients 35 and over and those patients with abnormal AFP testing or other reasons that put them at high risk for chromosomal problems. Nuchal lucency testing can be offered to all patients, regardless of age.

When combined the a simple finger stick measure of two blood markers (Genecare screen), the nuchal lucency ultrasound is able to detect 85-91% of affected Downs Syndrome babies in mothers below age 35. AFP triple screeing at 15 weeks, by comparison detects 65% of affected babies.

New statistical risks of having an affected child are calculated for patients who do these two tests, allowing the parents to make a more informed decision on whether to pursue amniocentesis.
Ultrasound of Abnormal Nuchal Lucency Thickening
It’s important to understand that amniocentesis is still the preferred tests for parents who want certainty of the chromosomes and is always recommended to confirm the diagnosis in those patients that have abnormal nuchal lucency/genecare results. Because the amniocentesis culture results take 10-14 days to return, many parents are faced with waiting until 16 or 17 weeks gestation before finding out the results of amniocentesis.

Nuchal luceny/genecare screening has not yet been approved for payment by many insurance plans, although many insurance plans are paying for the test. The cost out of pocket for the testing is approximately $300. Particularly, if you are under age 35, check with your insurance plan about what may or may not be covered.

In order to complete the screening process for neural tube defects, an AFP blood test is done later at 15 weeks.

In Phoenix, there are only a few radiologists qualified to perform nuchal lucency screening. Our office will help you make the appropriate appointments.

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