Tests for diagnosis in the first trimester are the set of tests designed to detect certain diseases or genetic disorders that can be performed during the first stage of the gestation period.
Among them, chronic villas sampling (CVS acronym) and amniocentesis are the only ones that can be made during the first quarter. The prescription of these aspects is taken into account such as age or medical history, among others.These prenatal tests evaluate the chromosomes of the developing baby. Chromosomes carry the genetic information that determines how a person. Normally has 46 chromosomes, 23 inherited from the mother and 23 from the father. The 23 chromosomes from each parent are peers within the nucleus of every human cell.
Twenty-two of these pairs are known as autosomes or autosomes , chromosomes that are not related to sex. The 23rd pair of chromosomes determines sex, and can be XX (girl) or XY (boy).
Women have two X chromosomes, so that can only bring the X chromosome to their children. The man has one X and one Y, therefore, can contribute either to their children. As you can see, the man who determines the sex of the baby.
Diagnostic tests in the first quarter tend to try to detect certain abnormalities in the number or structure of a chromosome that can potentially cause some problems in the baby.
For example, Down syndrome, which is one of the most common chromosomal abnormalities associated with severe mental retardation and occurs when the fetus has an extra copy of chromosome 21. This condition is also known as Trisomy 21.
In tests diagnosis in the first trimester, amniocentesis, chorionic villus sampling and other tests detect these abnormalities in chromosome number and structure. To do produce increased each call chromosome karyotype image.
Also, if a couple has a known risk of fathering a baby with a genetic disorder found in the family of one of the two or ethnic group, the physician may use the material obtained during these tests for testing to detect these disorders.
However, unless a couple of passing this specific risk of these rare genetic diseases, your doctor will do these tests in the first trimester diagnosis routinely, and the chromosomes are analyzed only in the number and structure .
Generally, women aged 35 or older are offered the opportunity to take prenatal diagnostic tests to check chromosomes of the fetus. Thirty-five years old is the basis for prescribing, almost obligatory, this type of testing.
This is because the risk of a woman having a baby with chromosomal abnormality increases significantly after reaching this age. Also, because it is the age at which the risk of spontaneous abortion to perform the procedure is equal to the probability that the fetus has a chromosomal abnormality.