AFP analysis in pregnancy: how to perform and what the study shows

Previously, deviations in the development of a child in the intrauterine period could be detected only after the baby was born. Later, ultrasound appeared, which provided sufficient information about gross anomalies in the development of the fetus, starting from the 10-14th week of pregnancy. A laboratory analysis for alpha-fetoprotein has become a worthy support for the instrumental method of examining expectant mothers. ACE during pregnancy is considered a fairly popular procedure, allowing already at the very beginning of the nine-month journey to identify and, if possible, prevent dangerous consequences for the child and his mother.

What does an ACE test mean during pregnancy?

In medicine, it is common to use abbreviations to denote many complex words and concepts. These are usually the first letters of different components of a certain concept. For example, the letter combination ACE is used to denote a specific protein found in the blood of any pregnant woman. It is called alpha-fetoprotein.

It should 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. However, its production is minimal and in a healthy person does not exceed 10 IU per ml of blood.

An AFP level of 0.5-10 IU/ml is considered normal for non-pregnant women. In essence, the AFP glycoprotein is an antitumor component and, if there is an active proliferative process in the liver or genitourinary system, which is typical for cancerous tumors, the body in response includes a kind of self-defense, starting to produce more antitumor protein. This is exactly what interests oncologists, because it allows them to identify tumor processes in the liver, genitals, and mammary glands.

An increase in the ACE concentration can be caused by any serious liver disease, such as hepatitis or cirrhosis, which are essentially an inflammatory and necrotic process in the organ tissues. In these cases, the analysis reveals the ACE content in the blood within 15-18 IU per ml. A further increase in the level of a specific protein indicates the development of a cancerous disease.

But this only applies to non-pregnant women. In expectant 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 AFP levels related? The female body is designed in an unusual way. It provides everything for the continuation of the family line, so that the woman can bear and reproduce her little copy. After the rupture of the follicle and the release of the egg, a temporary endocrine gland is formed in the woman's body - the corpus luteum, the task of which is to produce hormones that preserve and support pregnancy.

If conception does not occur, the corpus luteum dies, since it is not needed. In a pregnancy, a temporary gland producing estrogen and progesterone exists until the placenta is fully mature. It is in the corpus luteum that AFP is synthesized before it is produced in the embryo. It is not surprising that even non-pregnant women have higher levels of alpha-fetoprotein than healthy men.

While the corpus luteum exists, the concentration of ACE in the body of a pregnant and non-pregnant woman is approximately the same. But starting from about the 5th week of pregnancy, when the fetus's liver is formed and the beginnings of the digestive organs appear, the level of AFP begins to increase steadily, because alpha-fetoprotein is produced mainly in the liver and intestines of the human embryo.

At the beginning of the 2nd trimester of pregnancy, when the formation of the baby's digestive system is complete, and the products of its vital activity, including the AFP protein, begin to actively enter the amniotic fluid, the woman's blood test also changes, through which unnecessary substances are removed from the woman's body and amniotic fluid.

As the baby develops, the AFP content in the mother's blood also increases. Starting from the 33rd week of pregnancy, the formation of the baby's organs and systems is replaced by a period of growth, and the AFP level normally remains stable until the birth.

But what role does alpha-fetoprotein protein play in the development of the baby, because it is not for nothing that it is so actively produced in the child's body during the period of intrauterine development? Let's consider a number of its main functions:

• AFP is a type of transport protein, thanks to which proteins and polyunsaturated fatty acids, necessary for the construction of cell membranes and tissues of the baby, pass from the mother's blood into the blood of the fetus. This is necessary for the normal growth and development of the embryo, especially in the first two trimesters of pregnancy.
• The transport of essential unsaturated fats is also important in the last month of pregnancy, because fats participate in the formation of the surfactant alveolar complex, a compound that enables the baby to breathe independently after birth.
• AFP protects the child's body from the negative effects of the female hormone estrogen, the excess of which can cause unpleasant long-term consequences in the form of tumor processes in the reproductive system of an adult child.
• Helps maintain stable blood pressure in the fetal circulatory system.
• AFP is a kind of protection for the child from the aggressive impact of the mother's immune system, which can perceive the embryo as a foreign body. The protein reduces the synthesis of antibodies in the woman's body, which facilitates the bearing of pregnancy and reduces the risk of spontaneous miscarriage.

As we can see, the alpha-fetoprotein protein is an important indicator of the child's development and health, as well as evidence of how the pregnancy is progressing. At the same time, an alarming moment is both an increase in the AFP level 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 high risk of serious delays in the development of the fetus and early termination of pregnancy.

Doctors often use the abbreviation AFP to refer not only to the protein being tested, but also to the laboratory test prescribed during pregnancy. We will discuss the specifics of its implementation and the results of the study below.

Indications for the procedure AFP in pregnancy

Let's say right away that due to the increasing number of cases of early termination of pregnancy and the birth of children with all sorts of developmental anomalies, the relevance of prenatal (prenatal) diagnostic methods has increased significantly. If previously a woman could register at any stage and undergo a one-time ultrasound examination, now doctors simply insist that expectant mothers contact the antenatal clinic in the first weeks after conception, and better yet at the stage of pregnancy planning.

In this case, ultrasound can be performed several times during pregnancy, as well as various tests if the doctor suspects that the pregnancy is proceeding with some complications. We are talking about such laboratory tests as analysis for AFP, hCG, antibodies, hormones, etc.

Ideally, doctors recommend doing an AFP test during pregnancy already in the first trimester, which lasts up to 13 weeks after conception. The most suitable period is considered to be 10-12 weeks of pregnancy. However, this is only a recommendation for now. But in some cases, doctors may insist on an early laboratory test, and the reasons for this may be:

• a consanguineous sexual relationship between close relatives from which a child was conceived,
• a history of pregnancies that resulted in the birth of children with hereditary pathologies or developmental anomalies,
• late childbirth, if the expectant mother is already over 35 years old,
• previous miscarriages, stillbirths, long-term infertility treatment,
• the use of contraceptives or drugs by a pregnant woman before conception that can have a toxic effect on the embryo,
• the presence of hereditary developmental defects in a pregnant woman and episodes of such diseases in the family of both parents,
• alcohol abuse, drug use and smoking.

An AFP test should also be taken by women who were exposed to radiation, poisons and toxins, or ionizing radiation before or in the early stages of pregnancy. It is prescribed if the expectant mother had to have an X-ray in the first months after conception.

Based on the results of the analysis, doctors conclude that a repeat test is needed a little later (between the 13th and 20th week of pregnancy). Any deviation of AFP from the norm becomes an indication for repeat tests, which may indicate:

• various serious developmental abnormalities of the child,
• malfunctions and necrosis of the child's liver tissue, which is possible under the influence of a viral infection, alcohol consumption by the expectant mother, etc.,
• the presence of genetic abnormalities in the fetus,
• embryonic cell tumors, which most often develop in the testicles in boys or the ovaries in girls,
• serious liver diseases in the pregnant woman herself,
• development of liver, reproductive or sex gland cancer in the expectant mother.

Any of these doctor's suspicions must be confirmed or refuted using a range of studies, which during pregnancy include an ACE test.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ]

Technique AFP in pregnancy

Considering all the benefits and necessity of early diagnosis of fetal developmental abnormalities during pregnancy, the tests performed for this purpose must be taken seriously and responsibly. After all, even a general blood test requires some preparation, let alone a specific protein test. The best option would be to consult a doctor at a women's clinic about taking an AFP test, who will tell you when it is best to do it and how to properly prepare.

What are the requirements for preparing for an alpha-phenoprotein test that an experienced doctor will tell the expectant mother:

• one and a half to two weeks before the laboratory test, the pregnant woman should, if possible, stop taking any medications, since the active substances of the drugs, penetrating into the blood, can distort the indicators of fetal hemoglobin (hemoglobin of newborns entering the mother's bloodstream),
• the day before donating blood for AFP, a day before the procedure, you need to change your diet, eliminating fatty, salty or spicy foods, as well as fried foods and any types of alcohol (everything we eat affects the functioning of the digestive system and liver, so it can cause fluctuations in alpha-fetoprotein levels),
• the night before, you should avoid eating late, you can eat until 9 pm, so that you can visit the laboratory on an empty stomach in the morning,
• in the morning on the day of the test it is not forbidden to drink water, but its total volume should not exceed 100-150 ml,
• if it is not possible to take the test in the morning, it can be taken during the day, but at least 4-6 hours must pass from the last meal to the blood draw,
• A couple of days before the examination, you should reduce physical activity and rest more, because all this affects the functioning of our organs and can distort the results of any tests.

As we can see, preparation for the analysis does not imply major restrictions and special procedures, but it is very important for the accuracy and reliability of the results obtained after its implementation.

The process of taking blood is not very difficult either. Blood is taken from a vein with a 10-cc syringe. A rubber tourniquet is applied to the area of the middle of the woman's shoulder and she is asked to work with her fist, after which the doctor treats the area around the swollen vein with an antiseptic and removes the tourniquet. All that remains is to carefully make a puncture in the venous wall and take the required amount of blood.

After the procedure, a piece of cotton wool soaked in alcohol is applied to the wound and the woman is asked to hold her arm bent at the elbow for some time.

The volume of blood taken for analysis is 10 ml. Subsequently, the blood is examined using an apparatus for analysis and special reagents that allow the protein of interest to the doctor to be isolated and its concentration to be assessed per milliliter of blood, which is an important diagnostic indicator of the ongoing pregnancy.

Most often, this analysis is carried out in combination 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 taken simultaneously, which will have even greater diagnostic value.

Normal performance

In order to understand whether everything is normal with the expectant mother and her baby, doctors need something to rely on. That is, there must be certain norms of the AFP protein in the mother's blood, which indicate an uncomplicated pregnancy. But since the concentration of alpha-fetoprotein increases as the embryo develops, these norms are strictly tied to certain periods of pregnancy. Thus, in the first trimester of pregnancy, the AFP analysis should give much lower indicators than in the second, and after 32-34 weeks, the results of the laboratory study become uninformative.

But we are talking about short time intervals, so it makes sense to consider the APF norms not by months, but by weeks of pregnancy, which will help us with a special table, where the first column indicates the pregnancy period, and the second and third - the lower and upper limits of the norm.

From conception to 13 weeks	0.5	15
From week 14 to week 17	15	60
From 17 to 21 weeks	15	95
From 21 to 25 weeks	27	125
From 25 to 29 weeks	52	140
From 29 to 31 weeks	67	150
From 31 to 33 weeks	100	250
From 33 weeks until birth	Analysis is not carried out

Alpha-fetoprotein levels are given in international units (IU) calculated per 1 ml of a pregnant woman's blood. A unified system for designating concentrations helps avoid confusion and misinterpretation of diagnostic results.

According to research, up to the 13th week of pregnancy, the level of alpha-fetoprotein in the blood of a pregnant woman normally does not exceed 15 IU/ml. And after the 30th week, it reaches its maximum - 100-250 IU per ml, which is also considered normal. As we can see, the discrepancy in the figures is quite large both within one time period and in general during pregnancy.

As long as the ACE indicators during pregnancy do not exceed the upper or lower limits of the norm, the expectant mother has nothing to worry about. But indicators above or below the norm require additional research. And the greater their discrepancy with normal indicators, the more serious the situation.

[ 6 ], [ 7 ], [ 8 ]

Raising and lowering of values

An analysis of alpha-fetoprotein protein, which is one of the tumor markers, can be prescribed to both a pregnant woman and a person who is not planning to have a child. In the second case, the study is prescribed if a tumor process is suspected, and an excess of the AFP norm is considered a negative result. But during pregnancy, any deviation from the norm is considered dangerous, and it does not matter in which direction it occurred.

Most often, we are talking about normal or increased alpha-fetoprotein levels. Increased AFP levels during pregnancy may indicate the following disorders:

• the presence of not one, but two or more embryos (such a pregnancy is called multiple, requires special attention and is accompanied by the release of a double, triple, etc. amount of alpha-fetoprotein into the mother's blood),
• inaccurately established gestational age (an error of several weeks can be decisive, given how quickly the AFP concentration increases),
• infections in the blood of a pregnant woman, transmitted from mother to fetus and affecting the baby's liver, causing tissue necrosis,
• discrepancy between the body weight and size of the fetus and the established gestational age (large fetus),
• intrauterine growth retardation of the fetus,
• development of an umbilical hernia in an unborn baby,
• gastroschisis is a congenital pathology characterized by the presence of a defect in the abdominal wall of the fetus, through which some abdominal organs can fall out,
• disturbances in the formation and development of the neural tube of the embryo (the presence of a cleft in the spine, partial or complete absence of some parts of the brain, frontal bones and soft tissues - anesthephaly),
• developmental disorders of the kidneys (polycystic disease, absence of one or both kidneys, their underdevelopment, etc.) and the urinary system in a child in the embryonic period,
• chromosomal pathology accompanied by impaired physical development of the fetus (Shereshevsky-Turner syndrome),
• congenital pathologies of the digestive system caused by their improper formation (the presence of a blind end in the intestine or esophagus, their insufficient size, abnormalities in the structure of the stomach, etc.),
• dropsy of the brain in the fetus (hydrocephalus),
• placental pathologies, etc.

There are other pathologies and anomalies of fetal development that can be accompanied by an increase in AFP in the mother's blood, and their number is growing every year due to our ecology, nutrition, and bad habits. But the reason for a bad alpha-fetoprotein test can also be the health of the pregnant woman herself.

As we know, an increase in AFP levels both in everyday life and during pregnancy can be caused by developing liver failure, liver cirrhosis, hepatitis, tumor processes in the liver and sex glands. Risk factors include severe obesity in the expectant mother, diabetes, hypertension, and toxicosis in late pregnancy. Severe fetal malformations and serious health problems in the expectant mother create a risk of premature termination of pregnancy.

Low AFP during pregnancy is also not a reason to rejoice. After all, alpha-fetoprotein is considered an embryonic protein, and if there is little of it in the mother's blood, then there is insufficient production of this substance in the child's body, which is not normal, given the effect of AFP on the fetus. The reasons for a decrease in the level of alpha-fetoprotein in a pregnant woman can be:

• development of Down syndrome or other chromosomal abnormalities in the fetus, such as Patau disease with the presence of an extra thirteenth chromosome and multiple developmental abnormalities of internal and external organs, Edwards disease with various developmental defects caused by trisomy of chromosome 18,
• hydatidiform mole, which is characterized by the degeneration of the chorionic villi surrounding the fetus into vesicular structures similar to grape clusters (this pathology usually ends in the death of the fetus or termination of pregnancy, unless it is a case of twins, among which usually only one child survives),
• the death of a child in the womb, which requires urgent measures to save the woman's life,
• delayed fetal development, which results in a lower amount of alpha-fetoprotein being released than should be at a given stage of pregnancy,
• false pregnancy,

Low AFP levels during pregnancy may indicate a risk of miscarriage or premature birth.

[ 9 ], [ 10 ], [ 11 ]

Is there any cause for concern?

Pregnancy is a period when worry and anxiety about the full development of the baby in the womb is a privilege not only of the pregnant woman, but also of her relatives and, of course, the doctors who are monitoring the pregnancy. No matter how cruel it may sound, sometimes it is better to terminate a problematic pregnancy than to condemn a baby born with severe anomalies and developmental defects 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 take care of themselves, not to mention the fact that some children are born non-viable.

The earlier pathologies are detected, the less traumatic the termination of pregnancy will be for the fetus and its mother. And in some cases, early diagnostics helps save the life of the baby or its mother, which is also extremely important.

But even negative results of the ACE test during pregnancy should not be considered a death sentence and panic, especially since strong nervous experiences are harmful to expectant mothers. A laboratory test for alpha-fetoprotein can only indicate some violations, but its results are not enough to make a diagnosis. And a high level of AFP, diagnosed in 4-5% of pregnant women, may not be a reason for grief at all, because the cause of such a condition may be the news of double joy, if there are several daughters or sons in the mother's tummy.

In any case, to make an accurate diagnosis, doctors need the results of several diagnostic tests at once, which we have already mentioned. These are laboratory tests for hCG and hormones, as well as an instrumental test, popular among pregnant women and carried out not only to find out the number and sex of children before their birth, called an ultrasound scan (ultrasound). Only on the basis of the results of a set of diagnostic procedures can a doctor say with certainty what awaits a pregnant woman and her child.

And this is just a theory. In reality, quite a large proportion of women who received unfavorable prognoses based on AFP during pregnancy subsequently gave birth to healthy and strong children. In the end, the choice always remains with the expectant mother, unless, due to the serious condition of the woman, the doctors themselves will have to choose between saving the life of the child or its mother. But the principle of "hope dies last" has not lost its relevance, which means that you should hope for the best until the very end.