That a member of the couple is a carrier of a genetic disease is forcing the detailed study of another Member.
If you are thinking about becoming pregnant may be doubting if you should go to a geneticist, in which cases it is necessary, what evidence makes this doctor and what are for. Then we will try to answer you all these questions, and it is that, since a woman comes to your gynaecologist with the intention of becoming pregnant should start paying special attention to your health (and also of his partner), as that can influence, and much in the future baby. The medical professional in the preconception consultation will instruct you on how has to take care of yourself and what preventive measures should be followed to gestate a baby as healthy as possible. Women, for example, has begun already to take folic acid supplements to prevent malformation of the neural tube of your future child.
But, in addition, “the doctor should assess whether it is necessary to go to the geneticist. This must be an anamnesis (information gathering) complete to both members of the couple, emphasizing points of family history as mental retardation, congenital malformations, infertility or infertility, consanguinity (which the members of the couple are close relatives), cases of stroke or thrombosis in early age, or various types of cancers that could be inherited. One or more of these family history findings would advise a derivation of the couple to the consultation of genetics”, explains Miguel García Ribes, Coordinator of the Working Group of clinical genetics and rare diseases of the Spanish society of family and community (SEMFyC) medicine.
Obviously, any partner can access the genetics specialist consultation, but there are specific situations in which come to him would be suitable or necessary:
- Pregnant women with 35 years or more.
- Have already had a child with malformations, delay maturation, or other diseases of genetic origin.
- That the result of the triple screening blood is positive, “indicating a risk of a chromosomal abnormality in the fetus”, as says the doctor Juan Bernar Solano, head of the unit of medical genetics and Farmacogenómica of the Internacional Ruber Hospital.
- Women miscarried, since a high rate of miscarriages occur because the fetus has a chromosomal or genetic alteration.
- Women with low ovarian reserve.
- Alterations in prenatal ultrasounds.
- The mother is “exposed to any teratogenic (for example to radiation), or suffer an illness”, indicates the Ruber International Hospital expert. And, interestingly, adds, “couples whose genetic origin confers a special risk, for example the Jews”.
Finally, doctor Bernar Solano also points out that “to carry out an extended screening of carriers, that one member of the couple is carrier of a genetic disease is forcing the detailed study of another Member”.
From here, workers will begin to investigate possible genetic or hereditary problems that may arise. And it is that, as ensures the doctor Bernar Solano, “Genetics and its application to medicine is experiencing an extraordinary development. Currently has reliable diagnostic tests, and not excessive cost, that does three or five years were practically unthinkable. “To lead in its development remains United States, though virtually all genetic testing of clinical utility can be made in our country”.
Prenatal tests not invasive, as the triple screening or biochemical screening, do not involve fetal risk.
If in the course of your pregnancy you have referred to a geneticist, you should know that there are several genetic tests that we can be, depending on what has motivated the consultation this professional. Detect possible anomalies of the fetus that can do suspect a pathology of genetic origin, such as Down syndrome, or which allow to diagnose it directly through them. They are basically divided into:
You test non-invasive prenatal, i.e. that do not involve fetal risk. In this group is the triple screening or biochemical screening. It is a blood test that is performed in the first trimester of pregnancy and, looking at the values of certain hormones and protein alterations, indicating an increased risk of fetal malformations. It can be combined with ultrasound tests such as nuchal translucency ultrasound, which measures the thickness of the translucent space located at the nape of the neck of the fetus, in order to indicate the risk of a genetic defect in the baby.
There is also a genetic test based on the analysis of the DNA of the fetus in the mother’s blood and discover numerous trisomies – especially trisomy 21 (Down syndrome), 18 and 13 (associated with serious mental or physical disabilities) – and other chromosomal syndromes. This analysis can be performed from the 10th week of pregnancy and each time will progress more, expanding its diagnostic capacity. Although not detected all chromosomal alterations, yes the most frequent; in fact, it is reliable almost to 100% in the case of Down’s syndrome.
That Yes, it is necessary to clarify that these tests not invasive are not conclusive, they will have to confirm with other, but does serve to “put us on the track” potential problems.
* Invasive prenatal testing: the most common are the amniocentesis and the biopsy corial or villus sampling biopsy. This type of evidence is used, always under the advice of your gynecologist, when there has been any abnormal results during testing of screening for malformations during your pregnancy. Fluid from the amniotic sac is removed in amniocentesis, and chorionic biopsy takes a sample of cells from the placenta. It is also possible to obtain fetal blood accessing the umbilical cord (funiculocentesis or cordocentesis), although this type of techniques have directions much more selective.
Invasive tests, to be more precise, allow more safely find the existence of a genetic problem in the baby, but entail some risks such as damage to the fetus, or cause an infection. “The most feared complication in the case of invasive techniques is to cause a termination of pregnancy,” says Ismael Ejarque Doménech, Secretary of the Working Group of clinical genetics and rare diseases of the Spanish society of family and community (SEMFyC) medicine, because there is a probability of 0.5 to 1% of that to happen.
In addition, as the head of the unit of medical genetics and Farmacogenómica of the Hospital Ruber Internacional, Juan Bernar Solano, “may be necessary to make a karyotype, i.e., an analysis of the chromosomes of both parents to rule out the presence of a translocation (chromosomes genetic material exchanged between different chromosomes) in one of them that could explain, for example “, miscarried”.
Other available test, which takes place before the pregnancy, is called preimplantation genetic diagnosis, which is a form of early diagnosis of genetic alterations, widely used in the field of assisted reproduction. With her embryos and gametes healthy, avoiding genetic or chromosomal abnormalities are selected.
The fundamental thing is to inform parents of the existence or clear existing risk, and that they make a free decision.
If they have already made you any genetic testing during pregnancy, medical specialist already there will be able to collect all the information needed to issue a diagnostic which determine the risk or genetic problem of the future baby, if it is there it. From now on, it must give the couple corresponding advice, what is known as prenatal genetic counseling.
Although it depends on the type of problem or disease, and when it is found, the key is to “inform parents of the existence or the existing risk in a clear way, answering all their questions, and letting a free and non-directed decision about, if possible, terminate the pregnancy or go ahead with it”, as says Ismael Ejarque Doménech , Secretary of the Working Group of clinical genetics and rare diseases of the Spanish society of family and community (SEMFyC) medicine.
In Spain, law 2/2010 of Sexual and reproductive health and the voluntary interruption of pregnancy regulates the decision to have an abortion, fetal malformations and the chromosomal disorders as one of the reasons for this (although there are countries where restrictions are more railway and others, who have not even legalized abortion).
There will be other parents who decide to go ahead with the pregnancy, simply because it is the decision which best corresponds to its precepts ethical (or religious), or because medical assessment deemed that the alteration that the baby will have is not of extreme gravity and small, with proper treatment, you can have a normal life (for example, certain heart conditions cleft lip, or phenylketonuria, which can be controlled with a special diet). Obviously, professionals can advise, but they have a difficult decision to take parents. Especially in these cases, they will need will be much information and support from the outset, appropriate early treatments.
Finally, point out that for very specific, in origin, not genetic and structural problems and anomalies, there are options of ‘cure before birth’, thanks to the fetal surgery. For example, there have already been cases of interventions in a fetus with spina bifida, a congenital malformation that has a genetic component.