Most pregnant women have their first ultrasound at week 12 their gestation. This is when you take advantage of Triple Screening, a non-invasive test that consists in trying to find, if any, chromosomal alterations that could alter the growth of the future baby.
This will help to have a greater knowledge and get closer to what factors can increase the risk of certain pathologies. This test is not 100% conclusive but it will bring us closer to measure that risk index that may exist.
¿Qué es el triple screening?
This test is the so-called triple test. It consists of a blood collection where we try to look for evidence that chromosomal alterations may exist such as trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome) and defects in the neural tube.
In many cases, this type of test must take into account the mother’s age, the levels of two proteins found in the placenta (PAPP-A and free beta-hCG), and have evaluated a nuchal translucency test.
This kind of proof, as has been said, is only communicative but not conclusive. In the event that proof of some kind of conclusive data must be formalized with other types of tests that will be invasive. In this case you will have to do a fetal DNA test in the manternal blood, or an anmyocentesis or chorial bipsy.
Which women are taking this test?
Triple screnning is usually done to all pregnant women who may have a low risk of bearing a fetus with chromosomal abnormalities.
Women over 35 years of age, those who have had another type ofchromosomal abnormality in a previous pregnancy, women with repetitive abortions, who have had a family history related to Down Syndrome, who has been in contact with some type of radiation ionizing agents or women who have already had offspring of children with congenital malformations.
When is this sample performed?
It is performed during the first trimester of pregnancy and coinciding as a rule with the first ultrasound, around the 12th week of gestation.
At other times triple screening is performed at the beginning of the second trimester of pregnancy around the 15th and 18th week of pregnancy, but never after the 20th week, since the data that can be provided can not be very accurate.
How is the tripe screening test interpreted?
Once the blood test is done, your results will be expected in one or two weeks . The test has a diagnostic sensitivity ranging from85% to 90% success. When its result exceeds 1/250 for trisonomy 21,18 or 13 then we are considering that there is a high risk.
Other data must be collected, such as having found some form of fetal malformation on ultrasound or collecting data on a history of chromosomal abnormality in some other pregnancy or family history.
After these data, the results will be much better concluded with a chorial biopsy or aminiocentesis.
Other information on tripe screenig
Undergoing this type of test is not mandatory. It is important to have knowledge of what is going to be done, since it is a personal decision of the mother who wants to have such a test. This type of diagnosis we already know that it is to conclude mainly that the future baby will not have Down syndrome, as it is usually the most frequent syndrome. It is a question that the future mother has to ask, whether to get tested or not, because the decision to continue the pregnancy or not comes into debate and that falls on an indecision that can raise serious questions about its continuity.