During pregnancy, many different processes take place in the female body, the purpose of which is to create the most favorable conditions for bearing a baby, for its normal growth and development, to ensure maximum safety of childbirth. All these processes are monitored and controlled by doctors through a variety of analyzes. One of them is the D-dimer test. What this survey is, what it shows and why it is done, we will tell in this article.
What it is?
A lot during pregnancy depends on the correct functioning of the circulatory system. The volume of blood in the body of the expectant mother increases, because it is necessary to provide all the necessary substances, nutrition, vitamins at once two living organisms - a mother and a baby. Through the umbilical cord through the placenta, the child receives the mother's blood, enriched with oxygen and nutrients, and gives her back blood saturated with carbon dioxide and the products of his metabolism.
This exchange will be complete only when the woman's blood has the desired consistency - it is not too thick and not too liquid.
Special blood cells - platelets - are responsible for the density of blood and its ability to clot. Their task is to prevent bleeding and blood loss, to quickly "close" the wound site. This ability of platelets is extremely important in childbirth. If blood did not have such an amazing ability, then the birth of a placenta after a baby would always be accompanied by severe massive bleeding, dangerous for a woman's life.
Too thick blood can clog the blood vessels, so nature provides not only the process of thrombus formation, but also fibrinolysis - the dissolution of blood clots. The D-dimer analysis can tell about how these processes proceed in the blood of a pregnant woman.
D-dimer is called a small piece of protein that is formed during fibrinolysis. Blood clots are formed thanks to fibrin, which in case of danger associated with bleeding (in case of injury, injury, in childbirth), a special enzyme acts - thrombin. As a result, blood cells begin to quickly bind together to form a clot, closing the wound and preventing blood loss. This is a defense mechanism that saves a person's life.
As soon as the danger has passed, there is no longer a need for the formed blood clots. The body needs to get rid of them so that the vessels are not clogged. For this, another protein comes into play - plasmin, it starts the process of fibrinolysis. Clots under its influence gradually dissolve, disintegrate, blood vessels are cleansed, their patency is completely restored. And part of the substance that forms after the breakdown of febrin is called D-dimer.
What does the analysis show?
An analysis to identify the amount of D-dimer shows how both protective processes proceed in the human body - both the formation of blood clots and their subsequent dissolution. The body works normally when both processes are completely balanced. If there is a "bias" in one direction or another, the amount of the protein structure of the D-dimer will surely "inform" about this by changes in its concentration.
Thus, the result of the analysis will allow the doctor to judge the blood clotting of a pregnant woman - about the norm, about increased thrombus formation, which can lead to blockage of blood vessels and sad consequences, or about the low activity of febrin, which reduces the ability of blood to clot and increases the likelihood of severe bleeding. even with minor injuries.
Analysis appeared in the medical arsenal about 30 years ago. During this time, it has proved itself to be excellent, since the accuracy of the study is assessed as high. For pregnant women, he is appointed several times during the period of bearing a baby, the analysis is one of the mandatory diagnostic measures recommended by the Ministry of Health. Like other tests, a woman has the right to refuse to undergo such a diagnosis, but this will not be very reasonable on her part, because there is childbirth ahead, and the state of the blood is of great importance for their favorable outcome.
Indications for appointment
As already mentioned, a blood test for D-dimer is included in the list of mandatory laboratory tests for pregnant women. It is included in the list of blood clotting tests, which, in addition, includes tests for determining the time of clotting, tests for the content of fibrinogen, prothrombin, etc.
However, a woman may be assigned an unscheduled D-dimer test if her doctor has reason to believe that the expectant mother has problems with blood circulation. The doctor can suspect something was wrong by a number of characteristic symptoms:
If a pregnant woman complains of leg pain that gets worse when walking and standing upright. The skin in sore spots may have a paler color, the legs may swell. In this case, the analysis is recommended to exclude such a dangerous phenomenon as deep vein thrombosis.
If the expectant mother began to cough with blood impurities, while she complains of sternum pain and severe shortness of breath. In this case, the analysis allows you to find out if everything is in order with the vessels of the lungs.
If a pregnant woman looks pale, she has signs of cyanosis of the skin, she complains of strange pains in the heart, in the abdomen, bleeding gums, nausea and rare urination, as well as swelling of the hands and feet. Diagnosis of the D-dimer level in this situation is necessary to confirm or refute multiple vascular damage.
Frequent violations of the level of blood pressure in combination with edema and symptoms of toxicosis - vomiting, nausea and the appearance of protein in the urine - is also the basis for the appointment of a blood clotting test.
If the fetus detects the threat of hypoxia or the onset of hypoxia, then the woman will also be advised to donate blood for D-dimer. Abnormal fluctuations in this protein formation may indicate placental abruption.
In combination with ultrasound, the result will be the most accurate.
How is it done?
If a referral for analysis is received unscheduled, then special preparation for donating blood is not required. Blood sampling is carried out in the morning, the woman must come to the treatment room on an empty stomach. If the coagulation complex is planned to be determined along with a number of other tests in a planned manner, it is advisable for a woman to carefully prepare for the procedure.
If there are no separate indications for the determination of the D-dimer protein, then referral for this examination is included in the list of diagnostic techniques... In other words, a woman donates blood at the same time for several tests. For example, general analysis, biochemical analysis can be combined with a coagulation complex, and RW can be combined with HIV diagnosis.
A planned trip to donate blood should be preceded a two-day diet, in which a woman is advised to give up fatty foods, from a lot of sweets and salt, spices. For 2-3 days, you should, if possible, stop taking medications, if the doctor does not mind, and also reduce physical activity. It is important to minimize stress and anxiety, because they trigger certain processes in the body with the participation of certain hormones and enzymes, all this can "spoil" the clinical picture.
Indicator standards
All pregnant women are characterized by an increase in the blood D-dimer. The body of the expectant mother begins to prepare in advance for the upcoming birth, and therefore the amount of protein increases in trimesters. The longer the gestation period, the more fibrin breakdown product can be found in the woman's blood.
Before proceeding with the deciphering of the analysis, you should know that different laboratories use different methods for determining the protein structure, and therefore the numbers in the research form will vary greatly in different pregnant women. In addition, the ability of blood to clot is a rather individual indicator. That is why there are no strict norms for everyone, as such in nature. There are only recommendations for assessing the content of D-dimer in the blood of pregnant women.
For an adult, somatically healthy woman, it is considered normal if the level of this indicator in her blood does not exceed 500 ng / milliliter. But this applies only to non-pregnant women.
In an "interesting position" the picture changes somewhat:
During the first trimester, the protein content of the D-dimer constituent increases by about 1.5 times its baseline level before the woman becomes pregnant.
In the second trimester, the level of D-dimer rises by 2 times in comparison with the baseline level characteristic of this woman before pregnancy.
In the third trimester, the level of the substance triples from pre-pregnancy levels.
Thus, it is possible to accurately find out the individual rate of D-dimer only with the correct planning of pregnancy, when the first blood clotting test is done before conception. However, the majority of women in Russia do not bother with examinations before pregnancy, except for cases of infertility treatment, testing for IVF.
The rest come to the consultation after a delay in menstruation. And doctors have to analyze their blood for clotting, based on the maximum allowable D-dimer for an adult. This is how the generally accepted meanings for decoding appeared:
Table of the maximum amount of D-dimer in the blood during pregnancy:
Some laboratories use the protein product calculus in micrograms per milliliter. Then the density of the substance in the blood of a pregnant woman for weeks looks like this:
Table of D-dimer values by week:
Norms and deviations from them are not assessed independently by the D-dimer indicator alone. To obtain the most accurate picture of the processes occurring in the blood, the data on the density of the D-dimer should be correlated with the results of the coagulogram. If the doctor is not satisfied with the indicators of the protein compound in the blood, he will definitely prescribe a detailed coagulogram and, possibly, give a referral to a hematologist for consultation.
After IVF
Women who enter the in vitro fertilization protocol undergo a lot of tests before replanting and after embryo transfer. One of the studies is to necessarily determine the density of the D-dimer.
Different clinics treat this analysis differently.
Somewhere doctors prescribe an analysis twice, but somewhere they do it only once, when implantation after embryotransfer took place. Most often blood is taken 5 days after embryo transfer. There is a widespread opinion even among specialists that the implantation process itself can cause a drop in the level of D-dimer in the blood.
It should be noted that 97% of women who decide to become mothers through IVF this indicator in the blood is increased. Therefore, there is nothing surprising in the fact that doctors are "reinsured" and prescribe drugs to thin the blood after the embryos are planted in the uterus.
The reasons why the D-dimer in the blood of such pregnant women grows more rapidly are obvious - this is the implantation process itself, which is not easy for the woman's immune system, and the altered hormonal background, because during the IVF process, a woman necessarily receives hormonal therapy. Diseases that for some reason have not been identified earlier can also increase the density of the D-dimer.
After replanting, a jump in the D-dimer upwards can also occur due to multiplicity, after all, with twins or triplets, this indicator grows at a different pace. The protein level is also influenced by the hormone estradiol, which together with progesterone is very important for the successful attachment of the embryo.
D-dimer rates after embryo transfer with IVF:
Particular attention is paid to patients with a disturbing history. They can conduct a blood test in dynamics. These include:
- women for whom previous IVF attempts were unsuccessful;
- women whose close relatives have experienced strokes or heart attacks;
- women over 35;
- patients with identified violations of blood pressure and vascular problems;
- women who have previously had preterm birth, missed pregnancies, miscarriages, recurrent miscarriage.
Decoding
D-dimer is measured in several quantities - micrograms, nanograms, milliliters, μg FEU / ml (in micrograms of fibrinogen-equivalent units per milliliter). Therefore, it is important to check with the doctor What are the standards for the laboratory in which the blood test will be carried out. This will allow you to more accurately imagine the result of the survey.
The D-dimer exponent itself cannot indicate a specific disease, but if it is significantly overestimated, then this will be the basis for a more thorough examination of the expectant mother. From the tables presented above, it is clear that a reading of 1900 ng / ml at 7 weeks of pregnancy cannot be considered normal, as 1400 ng / ml in the first trimester.
If the D-dimer slightly exceeds the norm, for example, up to 774 ng / ml at 20 weeks, there should be no fear.
Deciphering the analysis should be dealt with by specialists, it is rather difficult for a woman to understand the complex biological processes of hematopoiesis on her own. In addition, in case of deviations, medical prescriptions will be required, and self-medication is completely inappropriate here.
Individual factors cannot be ruled out.... D-dimer levels rise with the same pattern in all women. Sometimes it rises only in the third trimester, and it is quite understandable, because the body is "mobilized" before childbirth. Sometimes the jumps only happen in the second trimester, and sometimes there are no jumps at all.
Reasons for deviations
As already mentioned, a diagnosis cannot be made on the basis of such an analysis. But the doctor will be alerted by the low level of the protein compound D-dimer, and the high one. Let's consider the most probable (but indirect!) Causes of changes in the density of this substance in the blood of a pregnant woman.
If increased
A significant excess of the norms for the content of this protein fragment in the blood may indicate the presence of blood clots. These assumptions must be supported by other tests that will show an increase in platelet count and a decrease in blood clotting time. A high D-dimer in this case will be an "indicator":
Thromboembolism is a life-threatening condition in which an existing blood clot breaks off and clogs a blood vessel. The consequences can be different, up to the rapid death of a person.
Disseminated intravascular coagulation syndrome or disseminated intravascular coagulation is a disease in which the formation of blood clots is disrupted and small vessels become clogged. This condition is massive, the functioning of almost all organs and systems is disrupted.
In this case, abnormal changes occur in the respiratory and urinary system, in the digestive organs, blood appears in the urine.
If the level of D-dimer is exceeded, but not significantly, then the doctor may suspect other diseases and conditions:
- the consequences of recent injuries (especially cuts, burns, open fractures, if any of the expectant mother);
- residual effects after surgery;
- ailments of the cardiovascular system, in which the destruction of the vascular walls becomes possible;
- oncological tumors;
- liver disease.
There are reasons for the growth of the D-dimer, characteristic only of women in an "interesting position":
- multiple pregnancy (twins or triplets);
- partial placental abruption;
- severe toxicosis with vomiting;
- diabetes mellitus, including gestational diabetes.
Thus, with the results of the coagulogram the woman will be referred for consultation to a cardiologist, oncologist, nephrologist, therapist. But this happens rarely, because a slight excess for pregnant women is a variant of the norm. Basically, additional diagnostic measures are required with a sharp jump in the density of a substance and a deterioration in the condition of a pregnant woman. If a woman has a slight increase in D-dimer, but her state of health does not cause concern, she does not complain about anything, she did not have injuries, then the doctor can assess this as a variant of the norm.
If there are complaints, and the problem with blood thickening is confirmed by related specialists and additional tests, the pregnant woman may be prescribed treatment with anticoagulant drugs that thin the blood. The specific drug and its strict dosage are determined by the doctor. A woman is prescribed an abundant drinking regime, this also helps to thin the blood. Thick blood creates problems with the transport of nutrients from mother to fetus.
If lowered
If you carefully look at the tables presented above, you can understand that it is quite difficult to imagine a reduced level of protein substance, because only the upper limits of the norms are indicated, and the lower ones are not indicated. therefore values from 0 and slightly higher are considered reduced by default.
If your result is exactly this, you can breathe a sigh of relief, because there are no blood clots in the body. But it’s not that simple. If a woman has neglected the rules for donating blood and came to the treatment room after a hearty breakfast, the results may be false negative - if the blood was taken too early - before the blood clot disintegrated, or too late - after the D-dimer was excreted from the body.
Therefore, there is a reason to retake the analysis in a few days.
A low D-dimer level indicates a decrease in platelet count and an increase in blood clotting time. This condition is very dangerous for a pregnant woman, because she can lose a lot of blood during childbirth. In addition, the risk of internal bleeding increases, which poses a fatal threat to both the woman and her child.
When such a problem is found, a woman be sure to go for a consultation with a specialist - hematologist, he studies in more detail the properties of the future mother's blood and decides on treatment. For therapy in this case, coagulant drugs are often used, which increase the viscosity of the blood mass.
For a baby in the mother's womb, liquid blood does not pose a danger, it does not in any way affect its growth and development, the main danger still exists for a woman. The reasons for conditional liquefaction (and it is considered conditional!) Are most often the following:
- hereditary blood diseases;
- oncological diseases, especially malignant liver tumors;
- low levels of hemoglobin in the blood;
- vitamin K deficiency;
- malnutrition.
It should be noted that problems with a decrease in D-dimer during pregnancy are extremely rare - usually these are isolated cases per hundreds of thousands of expectant mothers.
Prevention
There is no specific prevention of problems with blood clotting during pregnancy. Doctors recommend adhering to the correct daily routine, in which a woman will not experience strong physical exertion, and will devote enough time to sleep. It is important to saturate the diet with vitamins, especially vitamins C, B and K. Do not neglect the intake of folic acid.
It is because of disorders of folic acid metabolism that increased thrombus formation often occurs, its lack leads to increased vascular trauma, which increases the level of D-dimer in the blood. Diseases of the thyroid gland and kidneys increase the likelihood of hemostasis disorders, and therefore such pregnant women should visit a doctor more often, not to abandon planned and additional diagnostic measures.
See below for how an increase in D-dimer affects IVF.
