Chorionic villus sampling and amniocentesis have long examinations of prenatal diagnosis for excellence as they can know for sure if the fetus has abnormalities, particularly of chromosomes. Their main shortcoming is the risk of fetal loss, which is around 1%. For about a year, is available in Italian test harmless to mother and child, with a simple blood test maternal, can analyze fetal DNA results with almost comparable to those of chorionic villus sampling and amniocentesis. What are the differences between the two types of tests?
DNA testing fetal or CVS / amniocentesis: which to choose?
In Italy, as instructed by the Ministry of Health, when the expectant mother has exceeded the threshold of 3 5 years, may decide to undergo amniocentesis or chorionic villus sampling for free , since, statistically, overage, increases the risk that the fetus is affected by chromosomal disorders.
“In fact, the signs to undergo chorionic villus sampling and amniocentesis were downsized considerably whenever there are tests that can give results in part overlapping, without any risk for either the mother or the unborn child” highlights the prof. Luigi Fedele, head of the department of Obstetrics and Gynecology Clinic Mangiagalli of Milan. “We’re talking about the combined test of the first quarter (nuchal translucency more bi-test), but above all for taking the mother’s blood to analyze fetal DNA.”
This is a test developed in the United States in 2012 and arrived in Italy until the beginning of 2013, which, through a maternal blood sample, making the so-called selective sequencing, that analyzes the sequence of units that make up the DNA of the fetus and the pairs of chromosomes that are part of its genetic makeup, identifying any abnormalities.
DNA testing: what lets you know
For now, the test of maternal DNA is still considered a screening test, it is able to analyze only the chromosomal disorders more common, and that is the Down syndrome (or trisomy 21), Edwards syndrome (trisomy 18) and Patau (trisomy 13). “But thanks to the improvement of the method, it is expected that already within one year you can have with the test DNA sequencing complete, in order to make an examination of all comparable to amniocentesis and chorionic villus sampling” emphasizes prof. Fedele.