Blood Clots during Pregnancy

Pregnancy is a time of joy but also one of anxiety, stress and fear. One of the dangerous things you could face during your pregnancy is the threat of blood clots. Even though pregnant women only face a risk of 1 in 1000 of developing a blood clot, it is a highly critical condition and can lead to serious complications for you and your unborn baby. The important thing to do is stay calm in the face of pressure to deal with the many problems of pregnancy. Fortunately, there are several things you can do to protect yourself and your child from the dangers posed by blood clots.


What is a Blood Clot?

Your body can be injured in many ways. If your skin receives a cut, your body will send an army of special blood cells known as platelets to help. Platelets, along with an assortment of clotting factors, stick together to form a seal at the injury site, and stop blood from leaving the body. Clotting in such circumstances is an important bodily process to prevent blood loos. However, if a clot forms inside your veins and is unable to dissolve, this can become a dangerous situation.


Women face a much higher risk of developing a blood clot in the uterus during pregnancy than non-pregnant women. This is due to the raised oestrogen levels in their blood, which promote the activity of clotting factors. While the clot may not be dangerous in itself, depending on the location, it might cause severe complications. Blood clots can form at any time during the pregnancy or even for a few weeks after you give birth.

Types of Blood Clots?

There are two main kinds of blood clots that form inside the body. They are:

1. Thrombus

Blood clots that form inside veins or arteries are known as a thrombus. Thrombus clots can also develop inside the heart. A thrombus is basically a coagulated mass of red blood cells, platelets and fibrin protein. It can block healthy blood vessels and prevent blood flow, leading to a condition known as thrombosis. Generally, thrombosis occurs in the leg veins, but sometimes can happen elsewhere in the body. Thrombosis in pregnancy is quite common and very dangerous. The two main kinds of thrombosis are:

  • Deep Vein Thrombosis: Deep Vein Thrombosis, or DVT, occurs when a blood clot develops in a vein deep within the body, usually in the thigh or calf. It shows itself in the form of inflammation, swelling, pain, and warmth around the area that it is located in.
  • Cerebral Vein Thrombosis: Cerebral vein thrombosis, or CVT, is the formation of a blood clot in one of the brain veins. This greatly increases the chances of a stroke.

2. Embolus

An embolus is a clump of material that moves through the blood vessels. It is most commonly a thrombus that has dislodged from a blood vessel, but can occasionally be fat or air bubbles. An embolus during pregnancy can also obstruct the flow of blood in various organs in the body, giving rise to a condition known as Venous Thromboembolism. If it hampers blood flow to the heart, lungs, or brain, it could cause severe damage or even death.

What Causes Blood Clots during Pregnancy?

There are several reasons for the formation of blood clots during your pregnancy. Some of them are:

  • Cholesterol

Having cholesterol plaques clogging up your arteries will affect blood flow in that area, making you more susceptible to a thrombus.

  • Lack of movement

Standing or sitting for long periods can promote the development of blood clots in the leg. Make sure you don’t sit cross-legged for too long either.

  • Dehydration

Blood clots can develop in pregnant women who do not stay hydrated by drinking water or juices. Hyperemesis gravidarum is a sickness that could cause dehydration as well.

  • Recovering from surgery

If you have recently undergone invasive surgeries that involve cutting into arteries and veins, you face a higher risk of blood clots.

  • Damage to blood vessels

The increase in the size of your baby during pregnancy will start to put pressure on the veins that lead to the pelvic region. This makes it likelier for a clot to form in that region.

  • Certain medications

Some kinds of drugs, such as estrogen supplements or birth control tablets, can promote clotting.

Who is at the Risk of Getting Blood Clots in Pregnancy?

Developing a blood clot is uncommon, but the further you progress in your pregnancy the higher is the risk, peaking at the first month after your child is born. There are many risks that can cause blood clots during pregnancy. They are:

  • Family history

Heredity is one of the common causes of pregnancy blood clots. If women in your family have this tendency, it is likely you will too.

  • Certain medical conditions

Having illnesses like heart disease, sickle cell anaemia, thrombophilia, high blood pressure, diabetes or lupus greatly increases your risk of developing blood clots.

  • Age

Being over 40 makes your blood more likely to clot, so pregnant women above the age of 35 should take extra care.

  • Smoking

Smokers or second-hand smokers are at high risk of developing blood clots, as cigarette smoke tends to damage the inner lining of the blood vessels, as well as make platelets stickier.

  • Obesity

Having a BMI higher than 30 during pregnancy can cause reduced blood flow in the body, enhancing the formation of clots.

  • Ovarian hyperstimulation syndrome

Women who have been through fertility treatments can in rare cases develop this syndrome. Here, blood clots form as this condition results in injury to ovarian blood vessels.

Signs and Symptoms of Blood Clots while Pregnant

As a pregnant woman, you are prone to constantly worrying for both your health and your baby’s. Instead of fretting about another possible danger, just take note of all the signs your body is trying to show you. If you find yourself facing any of the following symptoms, you could have a blood clot and need to go to the emergency room immediately.

  • Chest ache or tightness
  • Bloody coughs
  • Finding it hard to breathe
  • Experiencing intense fatigue
  • Swelling and tenderness in the calf, thighs and lower back


There are several ways in which blood clots can be determined by your doctor. A few commonly used techniques are:

  • CT scan
  • Pulmonary angiogram to check for any embolus in the lungs
  • Ultrasound of the veins to visually check for clots
  • D-dimer test, which measures the level of clotting-related proteins to check for the chemical presence of blood clots
  • MRI of the veins to locate a thrombus
  • Contrast venography is the best method to identify clots but is quite expensive and invasive

Complications of Having Blood Clots in Pregnancy?

Thrombosis kills someone every five minutes. As the risks of blood clots during pregnancy are significantly increased, it could cause serious damage to both you and your unborn child. Some of the complications that can emerge in your body from developing pregnancy blood clots are:

  • Pulmonary Embolism

When an embolus moves from its initial location, it is driven around by the bloodstream. If it somehow makes it to the lungs, it is known as a Pulmonary Embolism (PE). PE is a type of VTE along with DVT. This condition can drastically reduce oxygen levels, damaging multiple tissues and organs in the body. The symptoms of PE are shortness of breath, feeling faint, irregular heartbeat and anxiety.

  • Myocardial Infarction

Also known as a heart attack, it can occur if the blood clot obstructs the heart muscles from receiving the oxygen and nutrients it requires. This could lead to the slow death of the heart tissues, causing a heart attack. Heart attacks can cause severe damage to the heart and are often fatal.

  • Ischemic stroke

The brain requires a constant supply of blood to function. Cerebral Vein Thrombosis can stop blood from reaching the brain, or in extreme cases, result in a bursting of the blood vessel. This is known as a stroke. Symptoms of a stroke are vision loss, dizziness, seizures, lack of feeling on one side of the body, and inability to move or speak. In many cases, strokes can lead to brain damage or fatality.

  • Preeclampsia

This is one of the most common conditions that some pregnant women go through, especially in their third trimester. Preeclampsia causes a rise in blood pressure, which affects the functions of the liver and kidneys. These organs may also be damaged if not treated in time. Some of the warnings signs of preeclampsia are headaches, protein in the urine, and unclear vision.

Can Blood Clots Affect your Baby?

Blood clots are not only dangerous to your health, but they can also cause severe harm to your unborn child, especially if they travel to the uterus. Blood clots can occasionally form inside the placenta, which will result in a blockage in the foetus’s blood supply. A few of the dangers they can cause to your baby are:

  • Placental dysfunction

As the placenta is the organ that serves as the oxygen and food highway between the foetus and the uterus, blood clots developing in the placenta will block the flow of blood to the foetus. This could put the life of your unborn child in serious jeopardy.

  • Foetal growth retardation

If the placenta is unable to function efficiently, oxygen and nutrients will not reach the foetus. This will result in the foetus developing incompletely or abnormally. It results in about 20% stillbirths, and the remaining 80% babies are likely to be underweight and might have developmental disabilities, obesity or diabetes in later life.

  • Miscarriage

Blood clots may also lead to the foetus dying before the third trimester, while still in the uterus.

  • Preterm birth

Blood clots can also lead to a premature birth, which means that the baby is born a week or more before its due date. These babies are underweight and might develop hearing conditions and vision problems, cerebral palsy, and lower IQ.

Can It Affect My Labour If I’m at High Risk of Getting DVT?

Deep Vein Thrombosis might be a debilitating condition, but you can still have a successful pregnancy even if you are at high risk. Reducing the risk of developing a clot until birth and for a few months afterwards is crucial. Some of the things you can do in your late pregnancy are:

  • Frequent movement will help keep the blood flowing through your body and reduce the chances of clots forming
  • Staying hydrated will prevent your blood from getting thick enough to precipitate clots
  • Aiming for a natural birth, as caesarean surgeries increase the risk of blood clots forming

How are Blood Clots Treated in Pregnant Women?

If the doctor observes blood clots in your body during pregnancy, there are several ways with which she might treat them.

  • Treatment with heparin or low molecular weight heparin

Heparins are a class of molecules that behave as anticoagulants. They prevent the formation of clots in the blood and thereby reduce the chances of getting deep vein thrombosis and pulmonary embolisms. This treatment will continue for at least 6 weeks after delivery.

  • Warfarin

It is an anticoagulant that is very efficient in treating DVT and PE, but is not recommended in pregnant women due to its side-effects, such as internal bleeding and tissue damage. A couple of weeks after you have given birth, your obstetrician will prescribe warfarin until all the blood clots have disappeared.

  • Inferior vena cava filters

New research is showing the promise of a technique which involves surgically inserting a small device into the inferior vena cava of the heart to reduce the risk of pulmonary embolisms. However, it has been found to increase the occurrence of deep vein thrombosis.


Due to the critical nature of pregnancy blood clots, there are some things that you must compulsorily do to keep them away from you and your child.

  • Stay active

This is the most important advice. In addition to advancing your cardiovascular health, getting physically active will keep your circulation in peak condition and not give your blood a chance to clot. Always ask your healthcare provider before you indulge in any kind of exercise while pregnant, especially if you are overweight. If you are medically advised to take bed rest during your pregnancy, anticoagulant medicines can keep the blood clots at bay.

  • Invest in compression pants

Wearing compression clothing will prevent damage to your veins and improve blood flow. This will also lower the chances of DVT.

  • Don’t sit all the time

Even if you have an active lifestyle, try not to remain seated or lying down when you’re at home or at work. Stand up now and then, take a short walk around the house or the office before getting back to what you were doing. Keep your leg muscles relaxed by giving them regular massages. If you’re travelling, make sure you get up and move around the car, bus, train or plane at least every half an hour.

  • Drink water

Drinking Water During Pregnancy

This is something crucial to our health, yet we still forget to do it enough. Most people need at least 2 litres of water a day. Pregnant women will do better drinking 3-4 litres every day.

  • Healthy lifestyle

Eating a balanced diet, that is lots of fruits, vegetables, lean meats, and whole grains, is important to stay healthy. Avoid smoking and alcohol as the former irritates the artery linings and the latter thins the blood.

Before you get overwhelmed by the amount of information you have just read, take a few minutes to relax and take a few deep breaths. Take everything one step at a time, and you will find yourself being able to handle the toughest of decisions. Now that you feel a little calmer, please understand that you have to face none of this alone; you have the support of your partner, family, friends and doctor to push through your difficult but rewarding time. Taking precautions against the dangers posed by blood clots is one of the most important things you can do to safeguard the health of your baby and yourself.