Investigation of chromosomal alterations
Early tests of fetal normality
By: Dr. Jonel J. Di Muro Ortega. Ginecólogo – Obstetra – Perinatólogo
It is a great concern for any father to know the “normality” of their future baby. A baby can be normal “anatomically” if its embryological development is perfectly achieved. This structural development can be checked by ultrasound since the first quarter, with emphasis towards the second quarter through morphological ultrasound or ecoanatomic.
But in the case of normality, in terms of correct number of chromosomes, the correct expectation is to have 22 pairs of chromosomes “Somatic” (corporal) and a sexual pair (which defines the genetic sex of the person). It is there that the settle aneuploidies or alterations of chromosome number, for example, stands out Down Syndrome with the appearance of a third chromosome 21 instead of two.
In the first trimester:
The most extended method of research is called Combined Test, which determines the statistical probability of risk for chromosomal syndromes and is constituted by the determination in the mothers blood of protein A associated with pregnancy (PAPP-A) and free Beta portion of Human Chorionic Gonadotropin (ß-hCG), associated with the evaluation and certified ultrasound measurement of the Nucal Translucency (NT) or thickness behind the neck and the Nasal bone (NB) of the baby. This is performed between 11 and 13 weeks + 6 days of pregnancy, with a detection from 85 to 91%.
In the second trimester:
Screening or triple screening test, also known as Triple Test, is constituted by the determination in mothers blood of Beta Human Chorionic Gonadotropin (ß-hCG), Non Conjugate Serum Estriol (E3), and Alpha Fetus Protein (AFP). The Triple Test allows the detection between 50 to 70% of the cases.
It is the right of every pregnant woman to approach as close to diagnosis of chromosomal normality of the fetus by using these innocuous and non-invasive tests.
Additionally, the supplement of ultrasound morphological of the second trimester determines the state of anatomical normality of the fetus. The final goal is to know and contribute the most information about the health and development of pregnancy and of the future baby.
Source: Dr. Jonel J. Di Muro O. Obstetrician – Perinatologist.