Introduction:
About 40 to 50 percent of miscarriages and other complications during pregnancy are due to disorders that increase blood clots. Many women with a blood clotting tendency have no symptoms before pregnancy because pregnancy can increase the risks of blood clots, particularly in women with a family history of blood clotting disorders.
Some studies suggest thrombophilias (blood clotting disorder) are linked with recurrent pregnancy loss. Many researchers report genetic blood clotting disorders commonly occur in women with recurrent miscarriages. However, treatment with Aspirin and Heparin can result in successful pregnancy in women with blood clotting disorders. Women with blood clotting disorders can also have successful pregnancies when their condition is properly managed. This article explains in detail about miscarriages occurring due to blood clotting disorders.
How Can a Blood Clotting Disorder Cause Miscarriage?
Blood clots can cause heart attacks by blocking blood flow to heart tissues. In the same way, blood clots can also block the blood flow to the placenta. This block can stop the flow of oxygen and nutrients to the newborn, which can reduce fetal growth and may lead to miscarriage. Blood clotting disorder can also interfere with the implantation (when the embryo settles in the uterus) and placentation (the formation and growth of placenta tissue inside the uterus), which can cause adverse pregnancy outcomes.
Pregnant women are susceptible to developing deep vein thrombosis (DVT) and pulmonary embolism (PE) because pelvic veins are the veins that reach the legs but are higher up. Thrombosis can occur in this vein and cause massive leg swelling. The ovarian veins can also get blocked during pregnancy and cause pelvic, abdominal, or side pain.
Blood clotting may also cause other pregnancy complications, including:
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Preeclampsia (increased blood pressure during pregnancy).
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Deep vein blood clots (venous thromboembolism and deep vein thrombosis) are where blood clots form in the limbs or lower body that may travel to the lungs and cause dangerous pulmonary thromboembolism.
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Miscarriage after ten weeks of pregnancy.
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Intrauterine growth restriction.
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Placental abruption (the placenta prematurely separates from the uterine lining).
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Stillbirth.
What Is the Blood Clotting Disorder That Occurs During Pregnancy?
Any disturbance or changes that reduce anti-clotting factors or increase clotting can increase the risk of blood clots during pregnancy. Thrombophilia can occur due to genetic or acquired causes. Many women are unaware of their inherited blood clotting disorder until pregnancy when they develop symptoms. It is even possible that nobody in a family knows about their family history of blood clotting disorder. The following are common blood clotting disorders (more than one can occur during pregnancy).
Blood clots occurring due to genetic causes include:
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Protein C deficiency.
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Protein S deficiency.
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Antithrombin III deficiency.
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Factor V mutation.
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Sticky platelet syndrome.
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Prothrombin gene mutation.
Blood clots occurring due to a combination of genetic and lifestyle causes are called partially inherited causes that include:
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Hyperhomocysteinemia (increase in homocysteine may be due to deficiency in folate, MTHFR variants, or other causes).
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High levels of factors VIIIc.
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PAI-1.
Blood clotting disorders that are developed later in life are called acquired which include:
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Lupus.
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Antiphospholipid syndrome.
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Other conditions that may increase blood clots include blood cancer, kidney and liver diseases, and inflammatory bowel disease.
What Is the Risk Factor for Developing Blood Clotting Disorders?
It is believed that deep vein thrombosis can occur due to several factors. Women are highly prone to experience a blood clot during their first three months of pregnancy or early after giving birth. If a woman suspects she is at risk for DVT, discuss this with a healthcare provider. The risk factors for blood clotting disorders include:
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Family history of DVT.
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Age over 35 years.
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Being overweight.
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Had a cesarean before.
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Smoking or being exposed to secondhand smoke.
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Traveling for a long distance during pregnancy.
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Expecting multiple births (twins, triplets).
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Being sedentary for long periods.
How Are Blood Clotting Disorders Diagnosed During Pregnancy?
The following tests can determine abnormalities in blood clotting, but the genetic mutations that cause it can not be determined.
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Activated Partial Thromboplastin Time (aPTT) - This test provides details on how fast the coagulation factors form a blood clot. If the aPTT is shorter, it indicates faster clotting time, which suggests a high chance of miscarriage. The reference range is 30 to 40 seconds. However, on anticoagulant therapy, it can be two times longer.
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D-dimer - D-dimer is a substance that forms after the degradation of fibrinogen. If there is a high D-dimer, it indicates ongoing thrombotic processes in the body. However, it is naturally elevated during any inflammation or pregnancy. Its reference range is 0.00 mg/L to 0.49 mg/L FEU.
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Anti-factor-Xa - This test measures the heparins in blood to determine whether the dose of anticoagulants is correct once the medications are initiated. Prophylactic dose ranges from 0.2 IU/ml to 0.5 IU/ml, and therapeutic dose ranges from 0.5 IU/ml to 1.2 IU/ml.
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Color Doppler Imaging - Color doppler imaging is a type of ultrasound imaging. It accesses the blood flow through uterine blood vessels. It helps to detect the blood vessel obstructions that could cause a thrombotic event.
What Is the Treatment for a Blood Clot During Pregnancy?
The following are the treatments for blood clots during pregnancy:
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Heparin - Blood clotting disorders are normally managed with low molecular weight Heparin to prevent venous thromboembolism during pregnancy. The dose may vary depending on the risk factors and the patient’s weight. Prophylactic doses are given to people with no other risk factors, while a therapeutic dose is given to those with an increased risk.
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Low-dose Aspirin - Aspirin is a nonsteroidal anti-inflammatory drug. It has a blood thinning effect, so it prevents heart attacks due to blood clots. Low-dose Aspirin is normally safe for pregnancy. It works by improving blood flow to the uterus and thinning the blood. However, it has side effects like a reduction in stomach mucous protection and ulcers.
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Diet and Lifestyle Management - Some blood clots worsen with increased body weight, diabetes, inflammation, and insulin resistance. So managing the lifestyle and diet can help to a certain extent.
Conclusion:
Blood clots during pregnancy can be harmful and cause miscarriage. The blood clot can be inherited, partially inherited, or acquired. If you experience recurrent early miscarriage, consult a doctor. These miscarriages can be easily treated and prevented.
