NIPT - Non-Invasive-Prenatal-Test for trisomies
The risk of having a child with a chromosomal anomaly is small. The basic risk depends on your age.
A Combined Test provides you with further information how low or how high this risk really is. It can detect over 90% of all trisomies, some other chromosomal anomalies and the majority of severe fetal anomalies.
However, the issue of trisomy 21 is of special interest for many families, since it is not only the most common chromosomal anomaly, but also because people with trisomy 21 have a close to normal life expectancy. Also pregnancy ultrasound can not identify all affected fetuses.
Since 2012 there are a number of special test available which can examine the small fraction of fetal DNA found in the maternal blood. These test are called Non Invasive Prenatal Test (NIPT - also known as Cell-free-fetal DNA testing) and can identify over 99% fetuses affected by trisomy 21, over 96% of fetuses with trisomy 18, and 92% of fetuses with trisomy 13. This test only identifies the most common trisomies, but no other developmental anomalies. Most fetal developmental anomalies (about 90%!) have no direct genetic origin.
Without a detailed ultrasound such as the ultrasound examination performed as part of a Combined Test NIPT does not pick up fetal developmental anomalies, and about 24% of possible signs of developmental anomalies will be missed.
At a maternal weight of less than 90 kg it is mostly possible to achieve a test result (in 99,5%). The success rate of the test falls with increasing maternal weight. A free retake mostly succeeds to provide a result even in these cases.
In rare cases the test gives a false positive result for trisomies even if the fetus is not affected. This happens in less than 1 in 1000 pregnancies. In case of a positive test (signs of a trisomy) an invasive test will be offered, as only such a test can give you 100% certainty.
The results of the test are available mostly within 14 days (mostly within 8-10 workdays).
Both you and your gynaecologist will be informed immediately upon receiving the test results.
Short take
- The test can be performed from 10+1 weeks of pregnancy.
- Currently the most sensitive non-invasive screening test for trisomies
- Even this test does not offer 100% certainty (it is not a diagnostic test)
- A short ultrasound is necessary to verify the positive heart action of the fetus and to determine ist length (CRL).
- The test is available also for twin pregnancies.
- It is highly recommended that a detailed ultrasound will be performed just as part of a Combined Test.
- it is bestsellers to combine NIPT with screening for preeclampsia which can identify most cases at increased risk for pregnancy complications like severe preeclampsia, fetal growth restriction and preterm delivery. In cases of screen positive result for preeclampsia an adequate and timely management and prophylactic treatment can consequently reduce the individual risk.
- To our best knowledge ultrasound does not harm the developing fetus
- Please be advised: information about the fetal gender is available only AFTER week 14!