Determination of various chromosomal pathologies in the early stages of bearing a baby is a very important task. To do this, doctors prescribe to expectant mothers a whole range of various examinations and laboratory tests. One of them is PAPP-A.
What it is?
PAPP-A is a very important laboratory indicator that is assigned to expectant mothers. It is included in the first prenatal screening. This spectrum of research is necessary in order to to identify various genetic pathologies at the earliest stages of their formation.
This substance appears in the bloodstream of a pregnant woman during pregnancy. It is highly specific. By its chemical and natural structure, it is a blood plasma protein.
The first four letters of the name of this substance are abbreviations. English-speaking experts call it Pregnancy-associated Plasma Protein-A. Translated into Russian, this means pregnancy-associated plasma proteins A.
Scientists believe that this substance appears in the mother's bloodstream when a small embryo is "implanted" (implanted) into the inner wall of the uterus. This leads to the fact that portions of PAPP-A are released into the blood.
Experts believe that the definition of the associated protein and the ratio of hCG are important indicators of various pathological conditions that occur in the very early period of a baby's development. This clinical indicator is a very important test for the detection of various fetal congenital malformations.
Chromosomal pathologies are quite dangerous. For a long time, doctors could not identify them in a timely manner.
Currently, it is possible to exclude dangerous chromosomal and gene diseases even during the period of intrauterine development of the baby. For this, specialists provide and analyze the results of various studies and analyzes.
Execution procedure
To determine PAPP-A, you will need to take some venous blood. It is better to take such a biochemical analysis in the morning, strictly on an empty stomach.
Only in some cases, a number of exceptions are allowed, when a pregnant woman does not come to the laboratory on an "empty" stomach. As a rule, such exemptions apply only to women who suffer from diabetes mellitus, especially the insulin-dependent type. In this case, they need to have breakfast.
On the eve of visiting the laboratory, you should limit the use of fatty and fried foods. They can lead to the result of the analysis being unreliable. In this case, the doctor may ask you to retake the test and prescribe an alternative test. Dinner in the evening before the test should be light and easy to digest.
Before passing biochemical tests, especially during the first screening, doctors strongly recommend that expectant mothers limit any physical activity... If a pregnant woman attends yoga classes for pregnancy or works out in the gym, then such workouts should be limited 3-5 days before the study.
When is it determined?
This laboratory study in most cases is carried out at 12-13 weeks. In some situations, it can be done a week earlier. The timing is determined by the doctor who observes the expectant mother in the antenatal clinic.
In addition to PAPP-A, other laboratory parameters are also determined. One of them is hCG. Its concentration increases with pregnancy. In the first half of pregnancy, its blood content is quite high. Only by childbirth does it begin to gradually decrease.
Specialists identify several special groups of women who should definitely undergo screening studies. These include expectant mothers who become pregnant after 35 years.
Women with related cases of chromosomal and genetic diseases must also donate blood for analysis and undergo an ultrasound examination.
Also, you should not avoid the passage of this set of studies for women in whom previous pregnancies ended in spontaneous miscarriages or early termination. Many experts also recommend screening for expectant mothers who have had some kind of viral or cold illness before 10-12 weeks of pregnancy.
Many expectant mothers mistakenly think that only an ultrasound scan during the first prenatal screening will be enough to reveal any pathologies. It's not like that at all.
During the ultrasound examination at this stage of pregnancy, only the basic indicators and dimensions of the fetus are assessed. If the research is carried out by a not quite experienced specialist, then the values of the results obtained may be incorrect. In this case, biochemical analyzes, including the determination of hCG and PAPP-A, help doctors identify dangerous pathologies already at an early stage of the baby's development.
Chorionic gonadotropin is a very important, but completely non-specific criterion. A change in its concentration in excess of the norm occurs in a variety of conditions. Not all of them are pathologies.
With multiple pregnancies, the concentration of hCG in the blood will be significantly increased.
Standards
Before evaluating the results of the analysis, the doctor will certainly take into account all the concomitant pathologies of internal organs that a woman has. It is also very important to consider whether the expectant mother is taking any medications. If PAPP-A is below or above the norm, then this requires careful attention to the woman in order to exclude dangerous pathologies.
In their daily practice, obstetricians-gynecologists often use a special table. It contains the values of the norm of this substance.
It is very simple and makes it quite easy to determine when the PAPP-A is increased or decreased. Normal values for this clinical indicator are presented below:
Reasons for the appearance of changes
Deviations from the norm should always be the reason for the targeted consideration of the risk of genetic and chromosomal diseases. Such violations may indicate the possible development of Down's disease.
An increase in this indicator in the blood can also be if the period of intrauterine development of the fetus was set incorrectly. This condition can also be with severe kidney disease of the mother, accompanied by the development of renal failure.
A lowered level of PAPP-A during the prescribed period of pregnancy can be a sign of "freezing" (suspension) of pregnancy. This condition is extremely unfavorable, as it can lead to spontaneous miscarriage.
A change in the concentration of this substance in the blood can be evidence of rather dangerous pathologies. One of them is Cornelia de Lange syndrome. This pathology is characterized by the development of a gene mutation. This disease is manifested by a disorder of psychomotor activity in a child.
It is important to note that multiple pregnancies are a special case. In such a situation, the doctor can detect both babies in the uterus by the 13th week of pregnancy. In this situation, the level of PAPP-A in the blood may be slightly different.
In order for the decoding of the test to be correct, doctors recommend donating blood for the determination of this substance with an interval of 3-4 days after the performed ultrasound examination. In this case, it is much easier for doctors to determine the possible pathology. Reviews of many women who have already become mothers indicate that they underwent an ultrasound scan and passed biochemical tests in just one week.
It is important to remember that only one result of the analysis in no case can establish any diagnosis. This will require the mandatory performance of ultrasound, as well as other biochemical laboratory tests.
In some cases, the appointment of alternative research methods will also be required. They are prescribed in cases where it is required to exclude the risk of having a baby with chromosomal or genetic abnormalities.
Such studies can be both invasive and non-invasive. They help doctors establish the correct diagnosis, and future mothers do not worry about the upcoming birth about the possibility of developing a chromosomal pathology in a child.
Non-invasive prenatal DNA test
The methods of prenatal diagnostics that are currently used are being improved. With the help of them, it is possible to identify various severe chromosomal and genetic diseases in the fetus even at the stage of its intrauterine development.
Many expectant mothers are intimidated by invasive tests. The excitement in this case is quite justified. The risk of possible complications after invasive prenatal diagnostic methods is quite high.
One of the alternative and more accessible methods, which is actively carried out for expectant mothers to exclude suspicion of chromosomal diseases, is a prenatal non-invasive DNA test. Its technique is that doctors study the genetic material of the fetus.
By conducting such a study it is possible to exclude the presence of many genetic diseases in the child - such as Down's disease, Edwards syndrome, Patau's, Turner's syndrome and many others.
Doctors who conduct this study, using special devices, can identify areas of microdeletion in the baby's genetic apparatus. These areas are gene breakdowns that are characteristic of genetic and chromosomal pathologies.
This test can be shown to all pregnant women who suspect the development of chromosomal diseases in a baby, regardless of their age.
Many expectant mothers think that this test should be done only by “old-born”. This is a big misconception. In some cases, this study is also indicated for women aged 20-25 and even during their first pregnancy.
You can take this test at several medical centers that conduct such research. The term for obtaining results "on hand", as a rule, is 12 days. It is important to note that according to American scientists, the accuracy of this analysis is 99.9%. You can conduct such a study as early as the 9th week of pregnancy.
The advantages of this test are numerous. This test is easy to do. It is not invasive. This means that the mother's belly, where the baby is located, is not pierced. In order to conduct a laboratory study, you only need some venous blood. Medical centers that are engaged in this type of research can send the results obtained by e-mail. The disadvantage of research is the high cost.
For information on what PAPP-A is during pregnancy and what its normal values are, see the next video.
