Thrombophilia during pregnancy is an anomaly of the blood clotting system, which often leads to thrombosis during gestation. The main symptoms of thrombophilia are thrombophlebitis, acute arterial and venous thromboembolism, vascular plexus lesion. As a result of pathology, there is often a violation of fetal blood flow and damage to the placenta. The main methods of diagnosis of thrombophilia include laboratory determination of hemostasis and specific antibodies, genetic testing. Specific treatment involves the use of anticoagulant drugs.
Thrombophilia is a hematological syndrome characterized by a tendency to thrombosis. Pathology usually manifests itself in the presence of provoking factors (during pregnancy, taking oral contraceptives, in the postpartum period). Thrombophilia is diagnosed in 4% of pregnant women. Most often (in 20-25% of cases) it accompanies antiphospholipid syndrome. The relevance of timely recognition and prevention of thrombophilia in obstetrics lies in the fact that this condition causes pregnancy complications in 3-80%.
Causes of thrombophilia
Hereditary and acquired thrombophilia are isolated. Hereditary thrombophilia is caused by congenital disorders in the blood coagulation system caused by genetic mutations. The carriage of abnormal genes in the absence of a provoking factor (pregnancy) may not manifest itself in any way. Hereditary thrombophilia include:
- Deficiency of antithrombin III. Its main function is the inactivation of clotting factors and thrombin, which stops the process of blood clot formation. Deficiency of formation or synthesis of low—activity antithrombin is a rather rare pathology, it occurs in 0.1%. The risk of pregnancy complications is 50%.
- Heterozygous Leiden mutation. In this pathology, coagulation factor V (Leiden) becomes resistant to the action of enzymes and actively promotes the formation of blood clots. It is detected in 4% of cases, causes complications in 6% of pregnant women.
- Homozygous Leiden mutation. It is the most dangerous of thrombophilia — pregnancy complications occur in 80% of cases. It is rare in the population, no more than 0.002%.
- Protein S or protein C deficiency. Normally, these enzymes destroy clotting factors, preventing thrombosis. Pathology is rare (in 0.5% of cases) and manifests itself from childhood. Complications during pregnancy reach 10%.
- Increased prothrombin levels. Gene mutations lead to an increase in prothrombin in blood plasma, which triggers the process of pathological clotting. In the heterozygous form, it occurs in 3% and gives complications in 3% of cases. In the homozygous form, pathology is rare (0.01%), but with a high risk of complications (30%).
Acquired forms of thrombophilia include antiphospholipid syndrome, in which increased clotting is due to the presence of antibodies to the body’s own cells. Also, an increased risk of thrombosis during pregnancy is associated with HIV infection. At the same time, both the disease itself and antiretroviral therapy contribute to the appearance of blood clots.
During implantation, the embryo damages the epithelium and vessels of the uterine mucosa. The mother’s body is forced to adapt through various rearrangements in order to prevent bleeding. One of the ways of adaptation is the activation of the blood clotting process. This is a normal defensive reaction. If a pregnant woman has thrombophilia, excessive clotting occurs. This leads to the formation of blood clots in the vessels. As a result, chorionic villi are damaged, the embryo implantation process is disrupted, pregnancy complications develop.
Symptoms of thrombophilia during pregnancy
During gestation, thrombophilia contributes to the occurrence of thrombosis. The symptoms differ depending on the location of the thrombus, the degree of blood flow disturbance and the diameter of the vessel. The most common complications include thrombosis of the lower extremities (thrombophlebitis). Characteristic signs are a change in skin color along the course of the damaged vein, an increase in local temperature, a feeling of bursting and pressing pain. When feeling, a seal is found in the place of the affected area, motor activity is disrupted due to severe soreness and convulsions.
Thrombosis in the placental vessels can cause severe gestosis, which is accompanied by high blood pressure, massive swelling of the lower extremities, arms, anterior abdominal wall, headaches. Pregnant women complain of a decrease in the amount of daily urine, tinnitus, flashing “flies” in front of their eyes. In the late stages of pregnancy, as well as within 2-3 days after delivery, eclampsia may develop against this background — brain edema with convulsive syndrome and loss of consciousness.
A dangerous condition is thrombosis of the branches of the pulmonary artery. Characteristic symptoms include a feeling of lack of air, shortness of breath, dry cough with wheezing. When breathing, chest pains occur, the skin becomes pale or cyanotic. This may be accompanied by fainting, vomiting, and heart failure. All types of thrombosis that occur during pregnancy on the background of thrombophilia need urgent medical care.
Thrombophilia during pregnancy causes severe complications. In the early stages of gestation, thrombophilia is the cause of frozen pregnancy, habitual miscarriages, and IVF failures. At a later date, a placental infarction with circulatory disorders may occur, which leads to a delay and abnormalities in fetal development.
With the detachment of a normally located placenta, bleeding develops, which can be massive and life-threatening for the mother and child. Thrombophilia increases the risk of myocardial infarction and strokes, premature birth. If a woman develops eclampsia during childbirth and the early postpartum period, this can lead to a fatal outcome.
Studies on thrombophilia are not carried out for all pregnant women, but only for those who have a burdened obstetric history. Women with habitual miscarriage and death of a newborn after premature birth, severe gestosis and placental abruption in previous pregnancies deserve special attention. To diagnose thrombophilia, laboratory tests are performed on:
- The level of antithrombin III. During pregnancy, it normally decreases, but the protein level should not fall below 70%.
- Protein C and protein S. Thrombophilia is indicated by a decrease in the level of these proteins below the reference values: for protein C, the plasma concentration is less than 70%, for protein S — less than 65%.
- Specific antibodies. The presence of antibodies to phospholipids and lupus anticoagulant is determined in the blood serum. Normally, they should not be detected.
- The presence of gene mutations. It includes the determination of gene mutations that most often lead to thrombophilia. A comprehensive genetic study allows you to determine the percentage risk of complications.
Treatment of thrombophilia during pregnancy
Unfractionated heparin and low molecular weight heparins are used in the treatment of the syndrome: nadroparin, enoxaparin, dalteparin. The duration of therapy is chosen by an obstetrician-gynecologist taking into account the leading syndrome. Women with a history of thrombophilia and obstetric losses are prescribed unfractionated heparin subcutaneously, starting from 4-5 weeks of pregnancy and up to 34 weeks. Further, it is impractical to continue anticoagulant therapy, since the placenta naturally begins to “age”, and treatment no longer affects the outcome of pregnancy.
If a pregnant woman has a history of thrombotic complications or during a real pregnancy, then anticoagulant therapy is carried out throughout pregnancy and after childbirth. The break in treatment for the period of delivery should be minimal. Low molecular weight heparins are convenient because injections are made less often than with conventional heparin treatment. However, they have no proven benefits for the fetus. Against the background of preventive treatment with heparin drugs, patients with thrombophilia do not need to prescribe other medications.
Thrombophilia is not a direct indication for cesarean section. On the contrary, the risk of thrombosis during operative delivery is twice as high as during natural childbirth, and the risk of thrombosis during emergency cesarean section is 2 times higher than that during elective surgery. However, in practice, such pregnant women develop pathological conditions in the form of gestosis, placental abruption, severe fetoplacental insufficiency. Therefore, approximately 70% of women with thrombophilia are delivered promptly. In the absence of emergency indications, the delivery period is 38 obstetric weeks.
Prognosis and prevention
With adequate preparation for pregnancy and preventive treatment, the prognosis for the woman and child is generally favorable. To prevent thrombosis, it is important to completely give up smoking, reduce weight (BMI should not exceed 30). Before planning a pregnancy, it is necessary to sanitize the foci of chronic infection, since the inflammatory process increases the likelihood of thrombosis.
During pregnancy, to prevent stagnation of blood in the lower extremities, it is recommended to wear compression stockings. It is important to regularly monitor the state of hemostasis and take a coagulogram at the time determined by the doctor.