Pregnancy: the first and second screening - we estimate risks of
Prenatal screenings cause a set of inconsistent opinions and responses. Someone is convinced of their need, others are sure of their full inexpediency. What researches and whether really all pregnant women have to pass them are? We decided to understand this question.
Prenatal screening is a complex of researches which main goal - to reveal risk group of pregnant women with possible malformations of the child (such as: Down syndrome, Edwards`s syndrome, defects of a nervous tube (anentsefaliya), Cornelia de Lange`s syndrome, Smith`s syndrome of Lemli Opitz, triploidiya, Patau`s syndrome).
In spite of the fact that skrinig include two enough checked diagnostics method - biochemical blood test and ultrasonography, their reliability and safety still cause a set of disputes.
Contra № 1: ultrasonic research harms the kid
there is quite popular belief that ultrasonography negatively influences nervous system of the child, irritates him - kids during inspection often try to hide from the device, cover the head with handles. Therefore children whose mothers regularly did ultrasonography during pregnancy are uneasier in comparison with kids whose mothers refused ultrasonic diagnostics. Whether so it actually?
according to doctors, ultrasonography cannot do to the kid absolutely any harm - the modern equipment is absolutely safe. Therefore the official medicine insists on that ultrasonography there passed all pregnant women. In due time carried out diagnostics allows, in - the first, to see a full picture of a course of pregnancy, and in - the second, in case of need, to correct these or those problems.Ultrasonic research is conducted by
at least three times for pregnancy (in the first trimester on 11 - 13 week, in the second - on 18 - 21 and in the third - on 30 - 32 week), but if necessary the doctor can recommend to pass it more often.Especially important the data obtained on ultrasonography of the first prenatal screening are considered as
(on 11 - 13 week of pregnancy). On this term during research:the quantity of embryos in a uterus, their viability is defined by
- ; by
- puts more exact term of pregnancy; by
- exclude rough malformations; thickness of vorotnikovy space - TVP is defined by
- (i.e. the amount of hypodermic liquid on a back surface of a neck of the child is measured - normal TVP should not exceed 2,7 mm); by
- investigates existence or lack of a nasal bone.
So, for example, at children with a Down syndrome the content of liquid strongly exceeds norm, and the nasal bone often is not visualized.
Contra № 2: biochemical blood test yields doubtful result
Many mothers are sure that cannot be made according to one analysis though how many - nibud reliable conclusions - too many factors can affect result. And partly they are really right. However it is necessary to study more attentively process of carrying out the analysis to understand on the basis of what the doctor does the conclusion.the Biochemical analysis is carried out by
to determine the level of content in blood of specific placentary proteins. During the first screening “the double test“ is done (that is the level of two proteins is defined):
- of PAPPA (pregnancy associated plasma protein or the plasma protein connected with pregnancy And);
- free a beta - subjedinitsa HGP (horionichesky gonadotrophin of the person).
Change of level of these proteins demonstrates risk of various chromosomal and some not chromosomal violations. However identification of the increased risk is not the certificate that with the kid something not so yet. Such indicators are only a reason for more attentive supervision over the course of pregnancy and development of the child. As a rule, if as a result of screening of the first trimester the risk on any indicators is increased, to future mother suggest to wait for the second screening. In case of serious deviations from norm indicators the woman is directed to consultation to the geneticist.
Carrying out the second screening falls
on 18 - 21 week of pregnancy. This research includes “threefold“ or “the fourfold test“. Occurs still, as well as in the first trimester - the woman makes blood test again. Only in this case results of the analysis are used for definition not of two, but three (or, respectively, four) indicators:
- free a beta - subjedinitsa of HGCh;
- an alpha - a fetoproteina;
- of a free estriol;
- in case of the fourfold test - also an ingibina And.
As well as in the first screening, interpretation of results is based on a deviation of indicators from average norm on these or those criteria. All calculations are perfromed by means of the special computer program then are carefully analyzed by the doctor. Besides, in the analysis of results the set of individual parameters (racial accessory, existence of chronic diseases, quantity of fruits, body weight, addictions etc.) is considered as these factors can influence value of the studied indicators.
to receive the most reliable results, data of researches of the first and second trimester in a complex surely correspond.
If as a result of researches I and II of a trimester some deviations in development of a fruit come to light, to the woman can suggest to pass repeated screening or at once will direct to consultation to the geneticist. If necessary he can appoint additional analyses for statement of more exact diagnosis (for example, research of amniotic waters, a biopsy vorsin a horiona). However because these researches are not absolutely safe and can become the reason of various complications of a course of pregnancy (risk of an abortion, development group or a Rhesus factor - the conflict, infection of a fruit, etc.) they are appointed only in case of high risk of pathology. Nevertheless similar complications meet not so often - in 12% of cases. And, certainly, all researches are made only with the consent of future mother.
Thus, the first two arguments contra, from the point of view of scientific medicine, are not convincing, and rather they should be reformulated so: prenatal screenings are safe for future mother and her kid, and all conclusions are drawn by the doctor taking into account the whole complex of individual factors.
Contra № 3:“ I have a good heredity - I do not need screenings“to
Some mothers all relatives do not see sense screenings - what problems can be are exciting to take place? Really, there are separate groups of women who first of all are recommended to pass research on detection of possible pathologies in development of the child. Women are more senior than
Contra № 4:“ I am afraid to hear the bad diagnosis“
It is, perhaps, one of the strongest arguments contra passings of screenings. Future mothers are very much frightened by probability to hear something bad about development of the kid. Besides, disturb also medical errors - sometimes screenings yield false positive or lozhnootritsatelny result. Cases when they said to mother that they at the child suspect a Down syndrome are known, and the healthy kid was born subsequently. Of course, of course, such news strongly affect an emotional condition of mother. After removal of a pre-trial detention the woman spends the rest of pregnancy in continuous experiences, and it is absolutely unhealthy for health of the kid too.However should not forget
that results of prenatal screenings do not form the basis for statement of the diagnosis at all. They only define probable risks. Therefore, even the positive result of screening will not be “sentence“ to the child. It is only an occasion to get professional advice of the doctor - the geneticist.
Contra № 5: it is impossible to correct the revealed potentially possible deviations in development of the child
It really so - there is no way to cure or correct chromosomal violations. Therefore impressionable and vulnerable mothers, and also women who are ready under any circumstances to keep the available pregnancy, can receive only an excess reason for experiences as a result of the passable screenings. Perhaps, it is valid, refusal of researches that mother could wait for the birth of the kid quietly will be the best exit in such situation.
undoubted plus of prenatal screenings is an opportunity on quite early terms of pregnancy to obtain information on development of the child, to descend on consultation to the geneticist, to pass if it is required, all additional inspections. Possessing data, future mother can already make quite consciously the decision on further development or interruption of pregnancy.
Most important argument contra: feeling sick of future mother at the time of research
Any, even slight increase of body temperature, cold (ORZ, a SARS), any other viral and infectious diseases and even a stress are unambiguous contraindication for carrying out screenings. Each of these factors can distort data of analyses. For this reason before going to take a blood test, future mother has to pass surely survey at the gynecologist - the doctor will estimate her general condition.
Today prenatal screenings are not strictly obligatory, however most of doctors are sure of need of these researches. The right of decision-making remains for the pregnant woman so, having weighed all pros and cons, each woman will make a choice - to someone important to control a situation and to obtain all possible information as soon as possible, and it is much quieter to someone to manage only an obligatory minimum of inspections, it is simple to rejoice pregnancies and to trust in the best.