What is a blood clot?
A blood clot is a mass of blood that forms when platelets, proteins, and cells in the blood stick together. When you get hurt, your body forms a blood clot to stop the bleeding. After the bleeding stops and healing takes place, your body usually breaks down and removes the blood clot. But sometimes the blood clots form where they shouldn't, your body makes too many blood clots or abnormal blood clots, or the blood clots don't break down like they should. These blood clots can be dangerous and may cause other health problems.
Blood clots can form in, or travel to, the blood vessels in the limbs, lungs, brain, heart, and kidneys. The types of problems blood clots can cause will depend on where they are:
- Deep vein thrombosis (DVT) is a blood clot in a deep vein, usually in the lower leg, thigh, or pelvis. It can block a vein and cause damage to your leg.
- A pulmonary embolism (PE) can happen when a DVT breaks off and travels through the bloodstream to the lungs. A PE, especially if it is large, can damage your lungs and prevent your other organs from getting enough oxygen.
- Cerebral venous sinus thrombosis (CVST) is a rare blood clot in the venous sinuses in your brain. Normally the venous sinuses drain blood from your brain. CVST blocks the blood from draining and can cause a hemorrhagic stroke.
- Blood clots in other parts of the body can cause problems such as an ischemic stroke, a heart attack, kidney problems, kidney failure, and pregnancy-related problems.
Who is more likely to develop blood clots?
Certain factors can raise your risk of developing blood clots:
- Atherosclerosis
- Atrial fibrillation
- Being overweight or having obesity
- Cancer and cancer treatments
- Certain genetic disorders
- Certain surgeries
- COVID-19
- Diabetes
- Family history of blood clots
- Overweight and obesity
- Pregnancy and giving birth
- Serious injuries
- Some medicines, including birth control pills
- Smoking
- Staying in one position for a long time, such as being in the hospital or taking a long car or plane ride
What are the symptoms of blood clots?
The symptoms for blood clots can be different, depending on where the blood clot is:
- In the abdomen: Abdominal pain, nausea and vomiting
- In an arm or leg: Sudden or gradual pain, swelling, tenderness, and warmth
- In the lungs: Shortness of breath, pain with deep breathing, rapid breathing, and increased heart rate
- In the brain: Trouble speaking, vision problems, seizures, weakness on one side of the body, and sudden severe headache
- In the heart: Chest pain, sweating, shortness of breath, and pain in the left arm
How are blood clots diagnosed?
To find out if you have one or more blood clots, your health care provider:
- Will do a physical exam.
- Will take your medical history, which includes asking about your symptoms.
- May order blood tests, including a D-dimer test.
- May order imaging tests, such as
- Ultrasound.
- X-rays of the veins (venography) or blood vessels (angiography) that are taken after you get an injection of special dye. The dye shows up on the x-ray and allows the provider to see how the blood flows.
- CT Scan.
What are the treatments for blood clots?
Treatments for blood clots depend on where the blood clot is located and how severe it is. Treatments may include:
- Blood thinners.
- Other medicines, including thrombolytics. Thrombolytics are medicines that dissolve blood clots. They are usually used where the blood clots are severe.
- Surgery and other procedures to remove the blood clots
Can blood clots be prevented?
You may be able to help prevent blood clots by:
- Moving around as soon as possible after having been confined to your bed, such as after surgery, illness, or injury
- Getting up and moving around every few hours when you have to sit for long periods of time, for example if you are on a long flight or car trip
- Wearing compression stockings after surgery or during a long flight
- Regular physical activity
- Not smoking
- Staying at a healthy weight
Some people at high risk may need to take blood thinners to prevent blood clots.
What is high blood pressure in pregnancy?
Blood pressure is the force of your blood pushing against the walls of your arteries as your heart pumps blood. High blood pressure, or hypertension, is when this force against your artery walls is too high. There are different types of high blood pressure in pregnancy:
- Gestational hypertension is high blood pressure that you develop while you are pregnant. It starts after you are 20 weeks pregnant. You usually don't have any other symptoms. In many cases, it does not harm you or your baby, and it goes away within 12 weeks after childbirth. But it does raise your risk of high blood pressure in the future. It sometimes can be severe, which may lead to low birth weight or preterm birth. Some women with gestational hypertension do go on to develop preeclampsia.
- Chronic hypertension is high blood pressure that started before the 20th week of pregnancy or before you became pregnant. Some women may have had it long before becoming pregnant but didn't know it until they got their blood pressure checked at their prenatal visit. Sometimes chronic hypertension can also lead to preeclampsia.
- Preeclampsia is a sudden increase in blood pressure after the 20th week of pregnancy. It usually happens in the last trimester. In rare cases, symptoms may not start until after delivery. This is called postpartum preeclampsia. Preeclampsia also includes signs of damage to some of your organs, such as your liver or kidney. The signs may include protein in the urine and very high blood pressure. Preeclampsia can be serious or even life-threatening for both you and your baby.
What causes preeclampsia?
The cause of preeclampsia is unknown.
Who is at risk for preeclampsia?
You are at higher risk of preeclampsia if you:
- Had chronic high blood pressure or chronic kidney disease before pregnancy
- Had high blood pressure or preeclampsia in a previous pregnancy
- Have obesity
- Are over age 40
- Are pregnant with more than one baby
- Are African American
- Have a family history of preeclampsia
- Have certain health conditions, such as diabetes, lupus, or thrombophilia (a disorder which raises your risk of blood clots)
- Used in vitro fertilization, egg donation, or donor insemination
What problems can preeclampsia cause?
Preeclampsia can cause:
- Placental abruption, where the placenta separates from the uterus
- Poor fetal growth, caused by a lack of nutrients and oxygen
- Preterm birth
- A low birth weight baby
- Stillbirth
- Damage to your kidneys, liver, brain, and other organ and blood systems
- A higher risk of heart disease for you
- Eclampsia, which happens when preeclampsia is severe enough to affect brain function, causing seizures or coma
- HELLP syndrome, which happens when a woman with preeclampsia or eclampsia has damage to the liver and blood cells. It is rare, but very serious.
What are the symptoms of preeclampsia?
Possible symptoms of preeclampsia include:
- High blood pressure
- Too much protein in your urine (called proteinuria)
- Swelling in your face and hands. Your feet may also swell, but many women have swollen feet during pregnancy. So swollen feet by themselves may not be a sign of a problem.
- Headache that does not go away
- Vision problems, including blurred vision or seeing spots
- Pain in your upper right abdomen
- Trouble breathing
Eclampsia can also cause seizures, nausea and/or vomiting, and low urine output. If you go on to develop HELLP syndrome, you may also have bleeding or bruising easily, extreme fatigue, and liver failure.
How is preeclampsia diagnosed?
Your health care provider will check your blood pressure and urine at each prenatal visit. If your blood pressure reading is high (140/90 or higher), especially after the 20th week of pregnancy, your provider will likely want to run some tests. They may include blood tests other lab tests to look for extra protein in the urine as well as other symptoms.
What are the treatments for preeclampsia?
Delivering the baby can often cure preeclampsia. When making a decision about treatment, your provider take into account several factors. They include how severe it is, how many weeks pregnant you are, and what the potential risks to you and your baby are:
- If you are more than 37 weeks pregnant, your provider will likely want to deliver the baby.
- If you are less than 37 weeks pregnant, your health care provider will closely monitor you and your baby. This includes blood and urine tests for you. Monitoring for the baby often involves ultrasound, heart rate monitoring, and checking on the baby's growth. You may need to take medicines, to control your blood pressure and to prevent seizures. Some women also get steroid injections, to help the baby's lungs mature faster. If the preeclampsia is severe, you provider may want you to deliver the baby early.
The symptoms usually go away within 6 weeks of delivery. In rare cases, symptoms may not go away, or they may not start until after delivery (postpartum preeclampsia). This can be very serious, and it needs to be treated right away.