The influence of the coagulation factor PAI-1 on thrombophilia in pregnancy

Thrombophilia is a condition that causes alteration in the blood coagulation leading to the formation of thrombi (clots). The formation of these thrombi within the deep veins, usually in the legs, increases the risk of obstruction of the vessel may cause a serious condition called thrombosis . To facilitate understanding, this disease is inversely proportional to hemophilia, in which the person ‘s body can not clot blood.

Thrombophilia can be inherited or acquired (obesity, smoking, diabetes, high blood pressure and the use of contraceptives are risk factors) and can affect both men and women. However, it is during pregnancy that many women discover a predisposition to thrombophilia due to a series of complications during pregnancy.

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Studies indicate that more than 60% of the predisposition to thrombosis are attributed to genetic factors. Thrombophilia affects about 15% of the population with pre-disposition. The molecular diagnosis detects the most common genetic mutations related to thrombosis and allows the structuring of a genetic counseling and family orientation program to accurately determine the genetic condition of the disease (hereditary or acquired). One of the mutations detected in the exam is a polymorphism in the promoter region of the PAI-1 gene known as 4G / 5G.

PAI -1 (plasminogen activator inhibitor type 1) contributes to the control of blood clotting. It can be secreted in different tissues such as: vascular endothelium, liver and adipose tissue. A high activity and concentration of PAI – 1 reduces fibrinolytic activity, which is associated with an increased risk of cardiovascular diseases and thrombosis. The 4G / 5G polymorphism is a common variation of the PAI-1 gene that is related to the plasma concentration of PAI-1. The 4G allele leads to higher concentrations of PAI-1, increasing coagulation; while the 5G allele results in lower levels of circulating PAI-1.

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Pregnancy is a state with complex metabolic and enzymatic interaction present in the coagulation process. During pregnancy the state of “hypercoagulability” of the maternal blood is to assist in uterine contraction and in the control of postpartum hemorrhage. That is why many women with thrombophilia discover the disease after some complication during pregnancy. The action of PAI-1 can cause thrombosis and induce placental insufficiency, preventing fetal development causing recurrent abortions, fetal death, placental abruption, early eclampsia, among other complications. This occurs especially when related to women with polymorphism of the 4G / 4G allele, which seems to respond by up to 47% increase in PAI-1 when compared to other alleles (4G / 5G and 5G / 5G).

Unfortunately, the test that detects the condition is only done after two or three abortions, causing suffering for the woman and her family. Many of them are unaware that they have a tendency to develop thrombophilia, the great advantage of  molecular diagnosis  is the prevention of all these effects in the family, especially in the mother. The examination data provide important information regarding the characteristics of the disease, risks of recurrence, modalities of genetic transmission and pre- and post-natal diagnosis.


Stay hydrated. Dehydration worsens the condition as it increases blood viscosity

Control your weight by practicing physical activities indicated by the doctor

Do not smoke

On a daily basis, use elastic stockings

Watch out for sudden bumps

Travel only with your doctor’s authorization


by Abdullah Sam
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