What is a good NT scan result?
What is a normal nuchal translucency measurement? An NT of less than 3.5mm is considered normal when your baby measures between 45mm (1.8in) and 84mm (3.3in) . Up to 14 weeks, your baby’s NT measurement usually increases as they grow. But after this, extra fluid can be reabsorbed.
What is abnormal NT scan?
The NT scan measures the clear (translucent) space in the tissue at the back of your baby’s neck. (This is the “nuchal translucency.”) Babies with abnormalities tend to accumulate more fluid at the back of their neck during the first trimester, causing this clear space to be larger than average.
How accurate are NT measurements?
NT results by themselves have an accuracy rate of about 70 percent. That means that the test misses 30 percent of babies with Down syndrome or other chromosome disorders.
Why NT scan is abnormal?
The results of a nuchal translucency scan may tell you if your baby has a high or low risk of a chromosomal abnormality. Examples of chromosomal abnormalities include trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome) or trisomy 13 (Patau syndrome).
What is the accuracy of a NT scan?
So a high risk result of an NT scan and high levels of these hormones tend to provide accurate indications that a baby will have Down syndrome. The rate of accuracy when a blood test and NT scan are done together increases to roughly 90%. However, with the combined test, the false positive rate is still five percent.
When to have a nuchal translucency ( NT ) scan?
First of all, the timing of this particular scan is very important. A woman must be 11 weeks, 2 days pregnant to 14 weeks, one day pregnant to have this scan for the best results.
What can I do if my NT scan results are positive?
After a positive result, your doctor may suggest another blood test called prenatal cell-free DNA screening. This test examines fetal DNA in your bloodstream to assess your baby’s risk for Down syndrome and other chromosome abnormalities. It can be frightening to receive inconclusive or positive results from an NT scan.
When do you get a NT scan during pregnancy?
A nuchal translucency (NT scan screens your baby for these abnormalities. This test is typically scheduled between weeks 11 and 13 of pregnancy. An NT scan is a common screening test that occurs during the first trimester of pregnancy.