What is the fetal fraction?

NIPS analyzes fetal DNA in the mother’s blood. The amount of fetal DNA in the samples is known as the fetal fraction. NIPS is only accurate at or after 10 weeks gestation because this is when there is a high enough fetal fraction to do the analysis. If the test cannot detect enough fetal material, a non-reportable result will be issued. This is also known as a low fetal fraction. Non-reportable results and results with low fetal fractions (below 3%) have been associated with a higher risk for a chromosome condition in that pregnancy. Women with these results should consider meeting with a genetic counselor to discuss the option of further screening (like a level II ultrasound) or repeating their NIPS later in pregnancy?

Can I have NIPS if I am pregnant with twins?

Yes! However, it is important to note if you have a fraternal twin pregnancy (where the babies each have their own placenta and amniotic sac) the results are less accurate than when used in screening a singleton pregnancy. This is because each twin’s placenta may not release the same amount of chromosome material into the mother’s bloodstream, leading to one twin being either underrepresented or overrepresented. Therefore, for twins, the risk is not reduced as much with a negative NIPS as it would be in a singleton pregnancy. However, NIPS is still the most accurate blood screening test we have for twin pregnancies for these conditions.

Does NIPS always accurately tell me the gender of my baby?

No! Fetal sex or gender, just like every other part of NIPS, is considered a screening test. While this is by far the most accurate part of NIPS, false results do occur. If you do receive an incorrect fetal sex prediction through NIPS, which is usually noticed at your 20 week ultrasound, do not panic. This does not necessarily mean anything is wrong with the baby. There are many reasons NIPS can predict the incorrect fetal sex or gender.

How does NIPS differ from first trimester screening?

Both are screening tests that assess the risk for Down syndrome and trisomy 18 in pregnancy by looking at a sample of a mother’s blood.

First trimester screening measures the levels of two proteins in the mother’s blood (PAPP-A and hCG) and combines those results with a 12 week ultrasound to look at a measurement on the back of baby’s neck called the nuchal translucency. Combining these numbers provides a risk for the pregnancy to have Down syndrome or trisomy 18.

NIPS looks at small pieces of chromosome material released by the placenta into the mother’s blood stream. No ultrasound is included for the risk analysis. NIPS additionally screens for trisomy 13 and sex chromosome (X and Y) differences in a pregnancy, as well as fetal sex. NIPS is also more accurate at screening for Down syndrome and trisomy 18 than first trimester screening. However, a nuchal translucency scan (part of the first trimester screen) can detect other concerns such as an increased risk for a baby to have a heart defect.

It is important to remember both tests are just screening tests and neither can diagnose or rule out a condition in pregnancy.

I heard my positive NIPS result may mean I have cancer? Is this true?

NIPS has detected a small number of cases of maternal cancer during pregnancy. However, these results look very different from a standard positive NIPS result. Often, these results come back positive for many chromosome conditions, giving both the laboratory and the genetic counselor an idea that something beyond the pregnancy may be going on. For example, these results will often say a baby has trisomy 18 AND monosomy 13, while the baby looks perfectly healthy on ultrasound. If you have had a positive NIPS result that turned out to be a false positive, you should not worry about an increased risk for cancer. Fortunately, most laboratories now can tell when an NIPS result is indicating the possibility of maternal cancer, and this would be discussed with you along with your results.

Is NIPS covered by my insurance?

Most insurance companies will cover NIPS for a woman of any age as it is the recommended test for all women interested in screening during pregnancy. However, some insurance companies deny all genetic screening and testing as an exclusion in their policy. If your testing is denied by insurance most NIPS companies will allow you to pay a reduced rate that can range from $100-$350 depending on the company. Ask your provider what company they use and what specific billing policy that company has to determine your exact price.

Is there anyone who should not consider NIPS?

Yes. Women who have undergone an organ transplant are not good candidates for NIPS. This is because small pieces of the organ donor’s DNA will be screened with the pieces of fetal DNA, giving an inaccurate result. Additionally, women who are currently affected with cancer should not undergo NIPS, since cancer cells often have chromosome differences that may lead to a false positive NIPS result. Finally, women on blood thinners such as Lovanox or Heparin are significantly more likely to have a non-reportable result, and should consider other screening options.

Should I get NIPS if I have a family history of birth defects? What about a family history of cystic fibrosis?

Standard NIPS only screens for Down syndrome (trisomy 21), trisomy 13, trisomy 18, Turner syndrome (monosomy X), Klinefelter syndrome (XXY), and other possible sex chromosome differences. Most birth defects are not caused by these conditions. Therefore, a negative NIPS cannot identify your risk for other birth defects or genetic conditions.

Meet the Shenal Family

Our daughter, Ryleigh, was diagnosed with a rare chromosomal deletion shortly after she was born in 2010. Since we received her diagnosis, the Greenwood Genetic Center has become part of our family. They made certain that we did not feel alone, and they continue to provide ongoing, compassionate care for our child. The impact they have had on our family and others across the globe everyday is immeasurable. We can't imagine walking this journey without...

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