In the previous entries we have explained in depth what triple screening is and when the pregnancy is performed, as well as everything necessary to correctly interpret the values of the test result.
Now we are going to address a topic that worries many pregnant women and is what to expect from triple screening. Knowing its advantages and disadvantages and what to do when the test yields a positive result, that is, a high risk of chromosomal alteration in the fetus.
It is important to remember at this point something that we have already explained. Triple screening is not a diagnostic test, but from a statistical test that, based on biochemical markers present in the maternal blood, establishes a risk index.
Advantages of triple screening
The main advantage of triple screening is that it allows to know through a non-invasive test (a simple analysis of the mother's blood) and in the first weeks of pregnancy, the probability that the fetus is a carrier of some chromosomal abnormality such as Trisomy 21 (Down Syndrome), Trisomy 18 (Edwards Syndrome) or a neural tube defect such as spina bifida or anencephaly.
Some women prefer not to know this probability and decide not to have the test. It is a very personal choice that every pregnant woman has the right to make.
Disadvantages of triple screening
The big disadvantage of triple screening is that an unfavorable result, naturally, generates anxiety in the pregnant Who thinks your baby may have a problem when it is often not like that. What was one more routine test becomes a double-edged sword.
The reliability of the test is not 100%, the diagnostic sensitivity is between 65 and 90, depending on when it is performed. There may be false positives (around 5%), that is to say that the test indicates a high risk of alteration in the fetus when there is none, which can be unnecessarily worrying.
There may also be false negatives, that is to say that there is an alteration that is not detected. With a favorable result, the pregnant woman presupposes that her baby does not have any anomaly when in fact she does, leaving the cut-off point from which more conclusive tests such as chorionic biopsy, amniocentesis or more thorough ultrasound are recommended.
When the result of triple screening is high risk
One of the worst moments facing a woman in gestation is knowing that something is wrong in pregnancy.
An unfavorable result in a prenatal test can be disconcerting, and I say it from my own experience. In my second pregnancy, triple screening showed a risk index of 1/153, that is, a high risk, recommending amniocentesis to "clear up doubts."
That triple screening of a high risk index It does not mean that your baby has a genetic alteration, but statistically, is more likely to have it.
When the result is positive or high risk, the pregnant woman is recommended continue with more conclusive but invasive studies, and therefore with risks, such as amniocentesis or
chorionic biopsy As the latter is more invasive, amniocentesis is generally recommended.
Amniocentesis and its risks
Amniocentesis is a test that It has its benefits, but also its risks. It is done by a puncture in the abdomen of the future mother with a long fine needle to extract amniotic fluid and analyze it.
It allows to have a confirmation, whether the baby suffers a chromosomal alteration or not, instead of following the pregnancy with the uncertainty of whether he will have something. Each couple should evaluate, if applicable, whether the benefit of confirming the diagnosis is greater than the risk or not.
As for the disadvantages of the test is that the risk of abortion attributable to amniocentesis is estimated between 0.5 and 1 percent. On average, it can be said that pregnancy loss occurs in one in 150-200 cases.
Performing amniocentesis can also cause loss of amniotic fluid or blood and carries a risk of urinary tract infections.
What decision to make?
It is a very difficult decision and very personal. The important is that the couple is well informed to choose the most appropriate decision. You can go to your gynecologist, a specialist in prenatal diagnosis and forums of parents who have gone through the same situation to know different opinions.
Basically, there are two paths to follow. The first is have amniocentesis assuming your risk of abortion that, although minimal, you have it, but knowing that if everything goes well in a few days (even if it seems like an eternity) you will have a confirmation.
At this point you have to see beyond. Think about what you would do as the anomaly is confirmed or not.
If the result of the amniocentesis is positive, that is, it is confirmed that the baby is a carrier of a chromosomal defect is the option to voluntarily abort (it is a legal right until the 22nd week of gestation) or to continue with the pregnancy assuming the consequences.
On the other hand, there are women who, although they do not think about interrupting pregnancy, prefer to have a certainty before delivery to prepare in time for what is coming, although the truth is that they are minimal cases.
The second way is do not have amniocentesis and continue with pregnancy. You can try to repeat the test to contrast the results or request more comprehensive ultrasound studies that can detect or rule out clues of possible abnormalities in the fetus.
My (unpleasant) experience with triple screening
I want to tell you my experience simply as an anecdote, with no intention of influencing anyone's decision.
As I told you before, In my second pregnancy, triple screening was positive. Despite being under 35, the risk index of trisomy 21 (Down Syndrome) was 1/153, so I was recommended to have amniocentesis (in the same consultation they gave me the flyers for amnio, without delays ). As you can imagine, I left the consultation made a mess, crying, bewildered, because you have to see the little tact that some doctors have.
As is the case with most pregnant women, at that time the gut was knotted and blocked, almost assuming my baby had a problem. Already calmer, at home, I began to inform myself to decide which path to take.
My reflection at that time was: I am advised to have a test with an abortion rate comparable to the risk of my baby having an abnormality. If the risk of amniocentesis is so "insignificant" why is it assumed that the risk of abnormality is "significant."
I think that before deciding to have amniocentesis, you should consider what you would do if the result is positive, that is, if it is confirmed that your baby has a chromosomal abnormality.
I was clear that I would have my baby come as it came, so I considered it unnecessary to take the risk of amniocentesis. What happens if I suffer an abortion? I don't know, call it intuition, but I decided not to have amniocentesis.
On the other hand, from that moment on, I performed more thorough ultrasounds, both for the private part of Social Security (for which four eyes see more than two), to detect possible ultrasound evidence related to Down syndrome and absence of nasal bone , control the growth of the baby, possible cardiac abnormalities, etc.
As the pregnancy progressed and the ultrasounds were normal I calmed down. Fortunately, my second daughter was born very healthy, but I assure you that until the moment of delivery I did not breathe finally relieved.
After this experience, and with the clearest things, in my third pregnancy I decided not to have the triple screening test.
Conclusion
I hope that with the three posts we have published about the triple screening in pregnancy, speaking in depth about this prenatal diagnostic test recommended by the SEGO, you can have a better idea of what to expect from the test and make the decisions that you think are most convenient.
Photos | oexenhave and Gabi Butcher on Flickr
In Babies and more | Triple Screening in the first trimester of pregnancy: what it is and when it is performed, Triple screening: how to interpret the values
