DVT (Deep Vein Thrombosis) in Pregnancy – Causes , Risks, & Treatment

Creator: Anisha Nair
Published: 2018-03-20 06:01:10

By Anisha Nair | Updated: 17/06/2026

Medically Reviewed By

Dr. Deepinder Kaur (Gynaecologist)

This health content has been medically reviewed by qualified experts and follows the FirstCry Parenting editorial policy to ensure accuracy and reliability.

Deep Vein Thrombosis (DVT) is a serious pregnancy complication in which a blood clot forms in a deep vein, usually in the leg, and pregnancy increases the risk of developing these clots by approximately five times compared to women who are not pregnant. According to the Centers for Disease Control and Prevention (CDC), women are at a significantly higher risk of venous thromboembolism (VTE), including DVT, during pregnancy, childbirth, and the first three months after delivery (1).

Understanding the link between DVT and pregnancy is essential because, although uncommon, untreated deep venous thrombosis in pregnancy can lead to life-threatening complications such as pulmonary embolism, where the clot travels to the lungs.

In this article, we’ll discuss the causes of DVT in pregnancy, its risk factors, warning signs, diagnosis, treatment options, and practical steps expectant mothers can take to reduce their risk and ensure a healthier pregnancy journey.

What Is Deep Vein Thrombosis (DVT)?

In deep vein thrombosis, clotting of blood occurs in the veins found in the legs and pelvic region. Clotting of blood is a normal physiological process in the body and occurs when there are any cuts or openings in the blood vessel. In the case of DVT, this occurs inside the vein, constricting the flow of blood resulting in serious implications, if left unidentified (2). Thrombosis in pregnancy is caused by an increase in the blood clotting capacity of the body during pregnancy, as a means of preventing excessive blood loss during delivery (3). This can sometimes result in a blood clot in the leg during pregnancy.

How Common Is DVT During Pregnancy?

DVT during pregnancy is not very common and occurs in one in a thousand pregnant women. The risk of developing DVT is six times more in a pregnant woman, with an increased chance of occurrence in the first trimester of pregnancy and six weeks post-partum (4).

Why Is It More Common During Pregnancy?

The body experiences numerous physiological changes during pregnancy. Variations in the hormonal levels mostly drive these changes. As a safety precaution, the clotting proteins increase, and the anti-clotting proteins decrease naturally in a woman’s body during pregnancy to minimise blood loss during delivery. Another factor that can contribute to this condition is the pressure exerted by the enlarged uterus on the veins which carry blood to the heart from the lower body.

Causes of DVT During Pregnancy

DVT is primarily caused by the hormonal changes the body undergoes during the pregnancy term. However, there are other reasons, too. Read on to know them.

1. Estrogen

During pregnancy, the circulating levels of estrogen hormone are high in the blood, which in turn increase the chances of a blood clot (5).

2. Uterine Growth

The expansion of uterus that occurs with the development of the foetus puts a lot of strain on the veins carrying blood back from the lower body to the heart. This also results in the clotting of blood inside the veins, returning from the extremities.

3. Increase in Body Weight

Excessive weight gain puts a lot of pressure on the veins of the legs and pelvis, thus increasing the chances of DVT (6).

4. Multiple Pregnancy

Mothers carrying more than one foetus in their womb have a higher risk of developing DVT (7).

5. Age and Genetics

Women who have a family history of DVT or are expecting a baby at 35 years of age or more are at risk of experiencing venous thrombosis during pregnancy.

Symptoms of DVT in Pregnancy

Pregnancy DVT signs can vary, but women often experience one or more of the following symptoms (2):

Pain in one leg accompanied by swelling.
Visibly enlarged veins.
Pain while walking.
The feeling of tenderness in the thighs and calf muscle.

Diagnosis of DVT During Pregnancy

Based on the symptoms and previous family history of DVT, the medical practitioner usually performs a Doppler ultrasound examination to check for any venous blocks. The Doppler ultrasound estimates the speed of blood flow in the veins and flags the areas that have reduced flow (8). The diagnosis of DVT can be very tricky, and in some cases, the doctor may prescribe a D-dimer test. This test works by identifying the presence of any blood clots in the blood vessels (9).

Doctors also carry out a venogram, in which a dye is injected into the veins to clearly visualise any blockage. This helps quantify and characterise the blockages (10).

Who Is at Risk of Getting DVT During Pregnancy?

Pregnant women who have one of the following risk factors have an increased susceptibility to developing DVT (11).

A family history of DVT
Previous history of DVT
Age above 35 years
Obesity or weight gain
Women who travel long distances during pregnancy
Smoking
Inactive lifestyle
Multiple pregnancies
C-section delivery
Clotting or inflammation due to infection in pregnancy

Treatment of DVT During Pregnancy

Once a diagnosis of DVT during pregnancy is made, the doctor usually prescribes medications to thin the blood. This medication is continued after delivery up to at least six weeks post-partum, as there are chances of blood clots even after the birth of the baby.

Does DVT Affect the Baby?

Typically, DVT causes discomfort to the mother but does not affect the baby’s growth and development (12). Rare situations when the block moves up till the lungs, affecting its function, it can hamper the oxygen supply to the foetus. Also, during delivery, when the mother loses excessive blood because of the blood thinners, it can affect the baby.

Management of DVT During Pregnancy

Management of DVT during pregnancy is possible with heparin injections. Heparin is an anticoagulant that inhibits the clotting of blood (13). Apart from the medication, some lifestyle changes like adopting an active routine, reducing body weight and quitting smoking can also largely prevent the further clotting of blood.

Special kinds of compression stockings can be worn to improve the blood circulation in the legs. Apart from that, drinking ample water and exercising also help manage DVT during pregnancy.

How to Reduce the Risk of DVT While Travelling?

Whether you’re travelling by car, train, or an aeroplane, taking a few simple precautions can help keep your blood flowing properly and reduce the likelihood of clot formation (14).

Stay well-hydrated by drinking plenty of water before and during your journey.
Keep your lower body moving by stretching your legs, flexing your ankles, and performing simple seated exercises.
Take regular walking breaks whenever possible, especially during long trips.
Avoid alcohol, as it can contribute to dehydration and reduced circulation.
Wear loose, comfortable clothing to prevent restriction of blood flow.
Consider using compression stockings if you are travelling for extended periods.

Prevention of DVT During Pregnancy

Some of the ways by which you can prevent the occurrence of DVT during pregnancy are (15):

1. Drinking Lots of Water

Fluid intake is very important in the prevention of DVT as it dilutes the blood and prevents it from becoming very thick. This has to be followed throughout pregnancy and even after delivery to prevent the formation of blood clots.

2. Exercising

If you are at the risk of developing thrombosis during pregnancy, then practising light and safe exercises regularly can immensely help in improving the blood circulation in the body. Exercises that particularly benefit the circulation of blood in the lower body can be helpful in preventing DVT.

3. Move on the Go

If you are having DVT and have to travel long distances on a regular basis, then try to move around inside the bus, flight or train every few minutes to break the resting period. This keeps the circulation alive. If getting up and moving around is not a possibility, then try to do simple twisting and moving exercises in the sitting position itself.

4. Wear Compression Stockings

Compression stockings that activate the blood circulation in the leg can be worn during pregnancy and even during labour to avoid clot formation.

When to Consult the Doctor?

While some symptoms may seem mild at first, certain warning signs require immediate medical attention:

Persistent swelling, pain, warmth, or redness in one leg.
Sudden shortness of breath, chest pain, or coughing up blood.
Symptoms that worsen quickly or do not improve with rest.

FAQs

1. Can Deep Vein Thrombosis affect labour?

To reduce the risk of developing thrombosis during labour, you can wear the compression stockings while constantly moving around and drink lots of fluids before going to deliver the baby. If you have already been diagnosed and are on heparin medications, the doctor may ask you to discontinue it as it can interfere with the clotting of blood after delivery.

2. Can caesarean delivery increase risk of getting blood clots?

Yes, a C-Section delivery is shown to increase the risk of post-partum blood clots, as compared to vaginal birth. This is because the body takes necessary precautions and mobilises its healing mechanisms for an invasive procedure, one of which is an increase in the propensity of the blood to clot.

3. Does the risk of DVT continue after delivery?

Yes. The risk of DVT and other blood clots remains higher during the postpartum period, especially during the first six weeks after childbirth.

4. How long does DVT treatment last during pregnancy?

The duration of treatment varies depending on the severity of the clot and individual risk factors. Many women continue anticoagulant therapy throughout pregnancy and for several weeks after delivery.

DVT is a common condition many pregnant women lack awareness about. It is easily treatable with medications, and identifying it at the right time is the key to have a safe and healthy pregnancy.

Also Read:

Blood Clots while Pregnant
Varicose Veins in Pregnancy
Spider Veins during Pregnancy
High & Low Haemoglobin Levels in Pregnancy

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