When a woman becomes pregnant, the main concern is that the future baby is healthy and safe during this period. Through so -called "non - invasive Prenatal Diagnosis Techniques" call "risk" for a particular birth defect is selected: among them we have the medical history, laboratory, ultrasound and various tests to rule out possible combined pathology.
If finally the specialist in Gynecology detects a risk factor, it is used to confirmation by the so - called "Invasive Prenatal Diagnosis Techniques". These tests are named by the certain risk of fetal loss involving; It is why it is not possible to universalize its use.
Noninvasive prenatal techniques
Among non-invasive techniques have the following:
-. History After making the clinical history of the patient, there are a number of situations that could already indicate the performance of some of the invasive tests detailed below. This will be done when maternal age is advanced, there is a history of pregnancy with anomalies or mental retardation, parents are carriers of a chromosome abnormality or a family history of birth defects, among others.
- Test of fetal DNA in maternal blood. It is from the 10th week, with the ability to know in a week the risk of Down syndrome (trisomy 21), the Edwards syndrome (trisomy 18) and Patau syndrome (trisomy 13). Furthermore, it can detect other abnormalities related to chromosomes X and Y, such as Turner syndrome and Klinefelter syndrome.
The sensitivity and reliability of the test is high, since it has higher detection rates of 99% with false positive rates as low as 0.1%. It is useful in multiple pregnancies and can be applied in all pregnancies achieved after assisted reproduction treatment, including in cases of egg donation.
- Analytics. Between weeks 9 and 12, two proteins can be quantified pregnancy. Beta-hCG and PAPP-A, pregnancy-associated plasma protein, which increases or decreases are related to the occurrence of some chromosomal diseases.
- Ultrasound. Ultrasound is the method of essential exploration in the field of prenatal diagnosis. Currently there are different: 2D, 3D and 4D color Doppler and pulsed Doppler, some of which offer high accuracy in the image.
Invasive prenatal diagnostic techniques
Invasive techniques allow complete diagnosis of many fetal pathologies, especially chromosomal diseases. They are not exempt from complications and carry some risk of interfering with the course of pregnancy. The most widely used techniques are:- Biopsy Corial. It aims at obtaining placental tissue, through the abdomen or via transcervical for the study of fetal chromosomes or more sophisticated studies like DNA or fetal enzymes.
-. Amniocentesis involves obtaining amniotic fluid surrounding the fetus through a needle through the mother 's abdomen. It is done between weeks 15 and 18.
-. Funiculocentesis is obtaining fetal blood through an umbilical vessel puncture guided by ultrasound. It is practiced from week 19-20 and is a technique much more selective indications.
Edited by Roser Berner Ubasos.