Genetic Testing with Non-Invasive Prenatal Screening (NIPS)

NIPS is a type of prenatal screening test that uses a simple blood test to check for any genetic abnormalities in a developing foetus. This test is considered non-invasive as it does not pose any threat or risk to the mother or her unborn baby. This test is performed in early pregnancy (around week 10) to determine the baby's risk of having chromosomal disorders or abnormalities.

The importance of genetic testing in prenatal screening cannot be overstated—it provides expectant parents with valuable information about the health of their developing baby and allows for early detection and management of any potential health issues.

How Does Genetic Testing with Non-Invasive Prenatal Screening Work?

NIPS is a safe and reliable prenatal screening method for most expectant mothers. It works by analysing foetal DNA in the mother's blood, collected at 10-13 weeks of pregnancy. This test helps parents make informed decisions about their pregnancy and the health of their developing baby.

The NIPS test is beneficial for women who are considered high-risk due to their age, family history, or previous test results and for women who are carriers of a genetic condition. It is also suitable for women who prefer a non-invasive prenatal screening method over other options, such as amniocentesis or chorionic villus sampling (CVS). It is recommended that women discuss their options and the suitability of NIPS with their healthcare provider to determine if it is the best choice for them.

Advantages of using NIPS over Traditional Prenatal Screening methods

There are several reasons why genetic testing with NIPS test is recommended and performed in early pregnancy and preferred over other forms of genetic testing:

1.     Non-invasive

Unlike traditional prenatal screening methods such as amniocentesis or chorionic villus sampling (CVS), NIPS uses a simple blood test that does not harm the mother or her unborn baby.

2.     Higher Accuracy

NIPS has a higher accuracy rate in detecting genetic abnormalities than traditional screening methods.

3.     Earlier Detection

NIPS can be performed earlier in pregnancy, starting at 10-13 weeks, compared to traditional methods that are performed later in the second trimester.

4.     Detection of More Conditions

NIPS helps detect a broader range of genetic conditions, including trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), trisomy 13 (Patau syndrome), and other chromosomal disorders.

5.     Reduced Risk of Miscarriage

Traditional screening methods, such as amniocentesis, carry a small risk of miscarriage, whereas NIPS does not pose any threat to the pregnancy.

6.     Convenience

NIPS is a simple blood test that can be performed in a healthcare provider's office, making it a more convenient option compared to traditional methods that require an invasive procedure.

7.     Cost-Effective

NIPS is often more cost-effective than traditional screening methods, especially when the cost of follow-up procedures is considered.

What to expect during and after the Genetic NIPS test?

There is no preparation required for this test. A blood sample is withdrawn from a vein in the mother's arm for the test.

Do You Need To Follow Precautions During or After The Test?

There are no precautions to follow before, during or after the NIPS test. It is natural to feel anxious until the results arrive, but mothers are advised to relax.

How Should You Interpret Results?

The test results you receive will usually arrive as 'low risk' or 'high risk'. 

• When the results report' low risk', it is unlikely the foetus has any chromosomal or genetic abnormalities that the blood sample was screened for. 

The most commonly screened conditions using the NIPS include- Down's Syndrome (trisomy 21), Edwards Syndrome (trisomy 18) and Patau Syndrome (trisomy 13). However, the test may sometimes include sex chromosome analysis and microdeletion conditions.

• When the NIPS test results come back as 'high risk', the baby is said to be at an increased risk of having a genetic abnormality identified. It is essential to understand that while this test is mainly good at identifying pregnancies with high risk for Downs syndrome, it may not be as accurate in identifying other trisomies. 

Parents must understand that a genetic NIPS is a 'screening test' and not a 'diagnostic test'.

• In cases with 'high risk' results, a diagnostic chorionic villi sampling (CVS) or amniocentesis may be performed on the placental tissue between the 10^th and 13^th week of pregnancy.

Are there Limitations of Genetic Testing with Non-Invasive Prenatal Screening?

Though the NIPS test is non-invasive and offers a great deal of information, we must understand that it has its limitations compared to other invasive diagnostic prenatal genetic tests. Some of these include:

1.     False-negative results

While NIPS is highly accurate, there is a small risk of false negative results, meaning that the test may not detect a genetic abnormality even though one is present.

2.     False positive results

Just like false negatives, a genetic NIPS can also give false positive results, meaning that the test may indicate a genetic abnormality even though one is not present.

3.     Limited diagnostic ability

As we have seen earlier, NIPS is not a diagnostic test but a screening one. A positive result will need to be confirmed through further testing, such as amniocentesis or chorionic villus sampling (CVS).

4.     Not suitable for all women

NIPS may not be suitable for all women, especially those with multiple pregnancies or those who have had a recent pregnancy loss.

5.     Limited detection of some conditions

NIPS may not be able to detect all genetic abnormalities and may miss some conditions that are only detected through other methods, such as amniocentesis or CVS.

6.     Emotional impact

The results of a NIPS test can have an emotional impact on expectant parents, especially if the results indicate a high risk for a genetic abnormality.

7.     Cost

While NIPS is often more cost-effective than traditional prenatal screening methods, it can still be expensive for some families.

Conclusion

Genetic testing with Non-Invasive Prenatal Screening (NIPS) is a safe, fairly accurate and common method of prenatal genetic testing that provides expectant parents with valuable information about their developing foetus. By analysing the mother’s blood sample, the NIPS can detect the presence of a wide range of genetic abnormalities and provides early insight into any potential health issues. While there are some limitations and potential risks associated with NIPS, the benefits of undergoing this type of testing can far outweigh these concerns.