Analysis of AFP in pregnancy: how to conduct and what the study shows
Deviations in the development of the child in the intrauterine period earlier could be detected only after the appearance of the baby. Later, there was an ultrasound, which gave enough information about the gross anomalies of fetal development, starting from 10-14 weeks of pregnancy. A laboratory analysis for alpha-fetoprotein became a worthy tool for the instrumental method of studying future mothers. ACE during pregnancy is considered a fairly popular procedure, which already at the very beginning of a nine-month path reveals and, if possible, prevents the consequences that are dangerous for the child and his mother.
What does the analysis of ACE in pregnancy mean?
In medicine, it is customary to use abbreviations to denote many complex words and concepts. Usually these are the first letters of different components of a certain concept. For example, the lettering of ACE is used to designate a specific protein found in the blood of any pregnant woman. It is called alpha-fetoprotein.
It must be said that alpha-fetoprotein is not a foreign substance for humans, it is produced in the digestive system (mainly in the liver) of men and women. True, its production is minimal and in a healthy person does not exceed 10 IU per ml of blood.
The AFP content in the limit of 0.5-10 IU / ml is considered the norm for non-pregnant. At its core glycoprotein AFP is an antitumor component and in the presence of an active proliferative process in the liver or urogenital system, characteristic of cancerous tumors, the body in return includes a kind of self-defense, starting to produce a greater amount of antitumor protein. It is this moment that interests oncologists, because it allows to identify tumor processes in the liver, genital organs, mammary glands.
Increased concentrations of ACE can cause any serious liver disease, such as hepatitis or cirrhosis, which are inherently inflammatory and necrotic in the tissues of the body. In these cases, the analysis reveals the content of ACE in the blood in the range of 15-18 IU per ml. Further increase in the level of specific protein indicates the development of cancer.
But this concerns only not pregnant women. In future mothers, a stable consistent increase in ACE is considered normal and in most cases indicates that the child is developing.
But how is the development of the child and the increase in the level of AFP? The female organism is arranged in an unusual way. It provides everything for the continuation of the family, so that a woman can bear and reproduce her small copy. After the rupture of the follicle and the release of the egg in the woman's body, a temporary endocrine gland is formed - the yellow body, whose task is the production of hormones that preserve and support pregnancy.
If conception does not occur, the yellow body dies because it is not necessary. With the pregnancy, a temporary gland producing estrogen and progesterone exists until the full maturation of the child's place occurs. It is in the yellow body that AFP synthesis occurs before it begins to be produced in the embryo's body. Not surprisingly, even in non-pregnant women, the level of alpha-fetoprotein is higher than in healthy men.
While there is a yellow body, the concentration of ACE in the body of a pregnant woman and a non-pregnant woman is approximately the same. But approximately from the 5th week of pregnancy, when the fetus forms the liver and the rudiments of the digestive organs appear, the level of AFP begins to grow steadily, because the production of alpha-fetoprotein occurs mainly in the liver and intestine of the human embryo.
At the beginning of the 2nd trimester of pregnancy, when the formation of the digestive system of the baby is completed, and the products of its vital activity start to actively enter the amniotic fluid, including the AFP protein, the analysis of the woman's blood also changes, through which unwanted substances are withdrawn from the woman's body and amniotic fluid.
As the baby develops, the content of AFP in the mother's blood increases. Starting from the 33nd week of pregnancy, the formation of the organs and systems of the child is replaced by a period of growth, and the level of ACE to the most genera in the norm remains stable.
But what role does the alpha-fetoprotein protein play in the development of the baby, it's not for nothing that it is so actively developed in the child's body in the period of intrauterine development? Let's consider a number of its basic functions:
- AFP is a kind of transport proteins, due to which the proteins and polyunsaturated fatty acids, necessary for building the cell membranes and tissues of the baby, from the mother's blood enter the blood of the fetus. This is necessary for normal growth and development of the embryo, especially in the first two semesters of pregnancy.
- Transportation of important unsaturated fats is important in the last month of pregnancy, because fats are involved in the formation of a surfactant alveolar complex - a compound that allows the child to breathe after birth.
- AFP protects the body of the child from the negative effects of the female hormone estrogen, exceeding its level can cause unpleasant long-term consequences in the form of tumor processes in the reproductive system of the child.
- Helps maintain a stable blood pressure in the fetal circulatory system.
- AFP is a kind of protection of the child from the aggressive impact of the mother's immune system, which can perceive the embryo as an alien body. Protein reduces the synthesis of antibodies in the body of a woman, which promotes pregnancy and reduces the risk of spontaneous miscarriage.
As you can see, protein alpha-fetoprotein is an important indicator of the development and health of the child, as well as evidence of how the pregnancy is taking place. At the same time, the alarming factor is both an increase in the level of AFP in relation to normal indicators, and too low indicators. In the first case, we can talk about health problems for both the mother and the child, and in the second there is a big risk of a serious delay in fetal development and early termination of pregnancy.
Abbreviation AFP doctors often call not only the protein itself, but also the laboratory analysis assigned during pregnancy. About the features of its conduct and the results of the study, we'll talk further.
Indications for the procedure AFP in pregnancy
We will say at once that due to the increased incidence of early termination of pregnancy and the birth of children with all kinds of developmental anomalies, the urgency of prenatal (antenatal) diagnostic methods has increased noticeably. If earlier a woman could be registered at any time and undergo a one-time examination of ultrasound, now doctors simply insist on that. That in the women's consultation, future mothers were already treated in the first weeks after conception, and even better at the stage of pregnancy planning.
In this case, ultrasound during pregnancy can be performed several times, however, as well as the delivery of all kinds of tests, if a doctor has crept into suspicion that the pregnancy is taking place with some complications. These are laboratory tests such as AFP, hCG, antibodies, hormones, etc.
Ideally, doctors recommend doing an AFP analysis during pregnancy in the first semester, which lasts until 13 weeks after conception. The most suitable term is 10-12 weeks of pregnancy. True, it is only a recommendation. But in some cases, doctors can insist on an early laboratory test, and the reason for this may be:
- a blood sexual relationship between close relatives, from which the child was conceived,
- the presence in the anamnesis of pregnancies that led to the birth of children with hereditary pathologies or developmental abnormalities,
- late birth, if the future mother is more than 35 years old,
- previous miscarriages, the birth of dead children, long infertility treatment,
- reception of a pregnant woman on the eve of conception of contraceptives or drugs that can have toxic effects on the embryo,
- the presence of hereditary malformations in a pregnant woman and episodes of such diseases in the genus of both parents,
- alcohol abuse, drug use and smoking.
The analysis on AFP should also be given to women who were exposed on the eve or early in pregnancy to the effects of radiation, poisons and toxins, the effect of ionizing radiation. He is appointed if the future mother had to do X-rays in the first months after conception.
According to the results of the analysis, doctors conclude that a second study is needed a little later (between the 13th and 20th week of pregnancy). The indication for conducting repeated analyzes is any deviation of the AFP from the norm, which may indicate:
- various serious anomalies of child development,
- malfunctions in work and necrosis of the liver tissue of the child, which is possible under the influence of a viral infection, consumption by a future mother of alcohol, etc.,
- the fetus has gene anomalies,
- embryonic-cell tumors developing most often in testicles in boys or ovaries in girls,
- serious liver diseases in the most pregnant,
- development in a future mother of oncology of the liver, the sex or sex glands.
Any of such suspicions of the doctor should be confirmed or refuted by means of a complex of studies, in which the composition of pregnancy includes the analysis of ACE.
Technique AFP in pregnancy
Considering all the benefits and necessity for pregnancy early diagnosis of fetal development anomalies, the analysis conducted for this purpose should be treated with all seriousness and responsibility. After all, even taking a general blood test requires some preparation, and what can we say about the analysis for a specific protein. The best option would be to consult about the AFP test with a female doctor who will tell you when to get it done and how to prepare properly.
What are the requirements for preparing the analysis for alpha-phenoprotein tell the expectant mother of an experienced doctor:
- for one and a half to two weeks before carrying out a laboratory test, a pregnant woman should stop taking any medications as much as possible, because the active substances of the preparations, penetrating the blood, can distort the fetal hemoglobin (hemoglobin of newborns entering the bloodstream of the mother)
- on the eve of blood donation to the AFP a day before the procedure, you need to change the diet, removing from it fatty, salty or spicy food, as well as fried foods and any kinds of alcohol (all that we eat is reflected in the digestive system and liver, fluctuations in the level of alpha-fetoprotein),
- on the eve of the evening it is necessary to refuse a late meal, you can eat until 9 o'clock in the evening, so that in the morning on an empty stomach to visit the laboratory,
- In the morning on the day of the analysis, it is not forbidden to drink water, but its total volume should not exceed 100-150 ml,
- if there is no possibility to pass the analysis in the morning, it can be taken in the afternoon, but at the same time from the last meal to the blood sampling must pass at least 4-6 hours,
- for a couple of days before the study should reduce physical activity, more rest, because all this affects the work of our organs and can distort the results of any analysis.
As you can see, preparation for the analysis does not imply large restrictions and special procedures, but it is very important for the accuracy and reliability of the results obtained after it.
The process of blood sampling is not very difficult. Blood is taken with a 10-cc syringe from the vein. On the middle of the shoulder, a woman is put on a rubber tourniquet and asked to work with a cam, after which the doctor treats the antiseptic area around the swollen vein and removes the tourniquet. It remains only to accurately make a puncture in the venous wall and take the necessary amount of blood.
After the procedure, a piece of cotton wool soaked in alcohol is applied to the wound and for a while the woman is asked to hold her arm bent at the elbow.
The volume of blood taken for analysis is 10 ml. Subsequently, the blood is examined with the aid of an apparatus for analysis and special reagents that make it possible to isolate the protein of interest to the physician and evaluate its concentration and a milliliter of blood, which is an important diagnostic indicator of the ongoing pregnancy.
Most often, such an analysis is carried out in conjunction with others. The standard diagnostic study of pregnant women is a trio of tests: ACE, hCG and gonadotropic hormone, which in many laboratories can be delivered simultaneously, which will have even greater diagnostic value.
Normal performance
In order to understand whether everything is normal for a future mother and her baby, doctors need to rely on something. That is, there must be certain norms of the protein AFP in the mother's blood, which indicate an uncomplicated pregnancy. But as the concentration of alpha-fetoprotein increases with embryo development, these norms are strictly bound to certain periods of pregnancy. Thus, in the first trimester, pregnancy analysis of the ACE should give much lower values than in the second, and after 32-34 weeks, the results of the laboratory study become already uninformative.
But it is a question of small time intervals, therefore to consider norms of ACE is sense not on months, and on weeks of pregnancy in what the special table where in the first column the term of pregnancy is specified, and in the second and the third - the bottom and top borders of norm will help.
|
From conception to 13 weeks |
0.5 |
15 |
|
From 14 to 17 weeks |
15 |
60 |
|
From 17 to 21 week |
15 |
95 |
|
From 21 to 25 weeks |
27th |
125 |
|
From 25 to 29 week |
52 |
140 |
|
From 29 to 31 week |
67 |
150 |
|
From 31 to 33 week |
100 |
250 |
|
From 33 weeks before delivery |
analysis is not carried out |
|
Indicators of alpha-fetoprotein are indicated in international units (IU), calculated per 1 ml of blood of a pregnant woman. A single system of concentration designation avoids confusion and misinterpretation of diagnostic results.
According to studies, before the 13th week of pregnancy, the level of alpha-fetoprotein in the blood of a pregnant woman does not normally exceed 15 IU / ml. And after 30 weeks it reaches its maximum - 100-250 IU per ml, which is also considered normal. As we see, the discrepancy in figures is quite large both within the same time period, and in general during pregnancy.
While the ACE indices during pregnancy do not go beyond the upper or lower limit of the norm, there is nothing to worry about the future mother. But indicators above or below the norm require additional studies. And the more their divergence from normal indicators, the more serious the situation.
Raising and lowering of values
The protein-alpha-fetoprotein analysis, which is one of the cancer markers, can be assigned to both a pregnant woman and a person who does not plan to replenish the family. In the second case, the study is prescribed if there is a suspicion of a tumor process, and a negative result is the excess of the AFP norm. But in pregnancy, any deviation from the norm is considered dangerous, and it does not matter which way it happened.
Most often it is a normal or increased content of alpha-fetoprotein. Elevated levels of AFP during pregnancy can indicate the following violations:
- the presence of not one, but two or more embryos (this pregnancy is called multiply, requires special attention and is accompanied by the release of a double, triple, etc. Amount of alpha-fetoprotein into the mother's blood),
- an inaccurately established gestation period (an error of several weeks can be decisive if one considers how rapidly the AFP concentration increases),
- infections in the blood of a pregnant woman, transmitted from mother to fetus and affecting the baby's liver, causing necrosis of her tissues,
- mismatch of body weight and fetal size with the established term of pregnancy (large fetus),
- intrauterine growth retardation,
- the development of umbilical hernia in an unborn baby,
- gastroschisis - congenital pathology, characterized by a defect in the abdominal wall of the fetus, through which some organs of the abdominal cavity may drop out,
- disturbances in the formation and development of the neural tube of the embryo (presence of a cleft in the spine, partial or complete absence of certain parts of the brain, frontal bones and soft tissues - anencephaly);
- disorders of kidney development (polycystosis, the absence of one or both kidneys, their underdevelopment, etc.) and the urinary system in the child in the embryonic period,
- chromosomal pathology, accompanied by a violation of the physical development of the fetus (Shereshevsky-Turner syndrome),
- congenital pathologies of the digestive system caused by their incorrect formation (the presence of a blind end in the intestine or esophagus, their insufficient size, disturbances in the structure of the stomach, etc.)
- hydrops of the brain in the fetus (hydrocephalus),
- pathology of the placenta, etc.
There are other pathologies and abnormalities of fetal development, which may be accompanied by an increase in AFP in the mother's blood, and every year their number grows because of our ecology, nutrition, bad habits. But the cause of poor analysis of alpha-fetoprotein can be the health of the most pregnant woman.
As we know, the growth in AFP indices both in normal life and during pregnancy can be caused by developing liver failure, liver cirrhosis, hepatitis, and tumoral processes in the liver and sex glands. Risk factors are severe obesity in a future mother, diabetes, hypertension, and toxicosis in late pregnancy. Severe fetal abnormalities and serious health problems in a future mother create a threat of premature termination of pregnancy.
Low AFP during pregnancy is also not an occasion for joy. After all, alpha-fetoprotein is considered an embryonic protein, and if it is not enough in the mother's blood, then there is insufficient production of this substance in the child's body, which is not normal, given the AFP's effect on the fetus. The reasons for reducing the level of alpha-fetoprotein in a pregnant woman can be:
- development in the fetus of Down's syndrome or other chromosomal abnormalities such as the Patau disease with the presence of an extra thirteenth chromosome and multiple anomalies in the development of internal and external organs, Edwards disease with various developmental malformations caused by 18 chromosome trisomy,
- a bladder drift that is characterized by the degeneration of the villi of the chorion surrounding the fetus into vesicular structures similar to the bunches of grapes (this pathology usually results in fetal death or abortion if it is not about twins, among which only one child usually survives)
- the death of a child in the womb, which requires urgent measures to save the life of a woman,
- delayed development of the fetus, in connection with which a smaller amount of alpha-fetoprotein is allocated in comparison with what should be at a specific period of pregnancy,
- false pregnancy,
A low level of AFP during pregnancy can indicate a threat of spontaneous miscarriage or premature birth.
Is there any cause for concern?
Pregnancy is a time when the excitement and experience for the full development of the baby in the womb is the privilege not only of the pregnant woman, but also of her relatives and, of course, the doctors leading the pregnancy. However cruel it may sound, it is sometimes better to interrupt the problem pregnancy, than to condemn the baby born with severe anomalies and malformations to eternal torment. After all, it is very difficult for such children to become full-fledged members of society, and many of them will never be able to independently service themselves, not to mention the fact that some of the children are born unviable.
The earlier pathologies are revealed, the less trauma for the fetus and its mother will be the termination of pregnancy. And in some cases, early diagnosis helps save the life of the baby or his mother, which is also extremely important.
But even negative results of the analysis on ACE during pregnancy can not be regarded as a sentence and panic, especially since future mothers are strongly affected by nervous troubles. A laboratory test for alpha-fetoprotein can only indicate some abnormalities, but its results are not enough to make a diagnosis. A high level of AFP, diagnosed in 4-5% of pregnant women, may not be an occasion for grief, because the cause of this condition may be the news of double joy, if in the tummy of the mother sit several daughters or sons.
In any case, to produce an accurate diagnosis, doctors need the results of several diagnostic studies, of which we have already mentioned. These are laboratory tests for hCG and hormones, as well as instrumental research, popular in pregnant women, conducted not only to find out the number and sex of children before their birth, called ultrasound (ultrasound). Only on the basis of the results of a complex of diagnostic procedures the doctor can accurately say what a pregnant woman and her baby are waiting for.
And this is just a theory. In reality, a fairly large proportion of women who received unfavorable prognosis based on AFP during pregnancy subsequently gave birth to healthy and strong children. In the end, the choice is always for the future mother, except that because of the plight of women, doctors themselves have to choose between saving the life of the child or his mother. But the principle "hope dies last" has not lost its relevance so far, which means that the best is to be hoped for to the last.