Blood Thinners in Pregnancy: Weighing the Risks and Benefits

Pregnancy is indeed a beautiful journey but can be especially stressful for women with heart conditions. Consuming blood thinners during pregnancy can put you in a state of turmoil. Questions may arise, such as, Does blood thinner make you tired? and whether its usage is beneficial or risky becomes a serious conundrum.
Expecting women are at a five times higher risk of experiencing clotting. This happens because, during pregnancy, the blood clots more quickly to ensure less blood loss during labor and delivery. However, this natural protective mechanism can potentially interfere with your heart health and introduce complications into your pregnancy.
On the contrary, if you continue taking the prescribed blood thinners, the clotting process may slow down, causing lesser harm.
Blood Thinners in Pregnancy
When you are expecting, there are a lot of complications that can also hinder your heart disease management process. While it is advisable to consult your healthcare provider before you stop taking your medications, here are some pros and cons of consuming blood thinners in pregnancy.

Why are Pregnant Women At High Risk?
Expecting a baby is the happiest time of a person’s life, but it can be stressful too. No, not only because of the parenting stress but also due to the increased risks because of your heart health. Out of all women suffering from cardiovascular issues, at least 10% are at high risk. Additionally, for some pregnant women with certain heart conditions, blood thinners may be necessary to manage their health. However, it is essential to be aware of the risks of blood thinners during pregnancy and consult a healthcare professional for personalized guidance.
These medications might interfere with the development of your fetus. Here are a few reasons why expecting mothers should learn about the risks and benefits of blood thinners in pregnancy.
- Hormonal changes
- Hormonal imbalances can affect the blood clotting rate, and certain clotting factors increase in the blood during pregnancy which curbs excessive bleeding at the time of delivery.
- As much as it is beneficial, it is also harmful to mothers with a preexisting heart condition as it increases the risk of blood clot formation, causing complications in treating cardiovascular illnesses.
- Changes in blood flow
- During the pregnancy, the uterus expands, which puts pressure on the veins in the pelvic region and further down, increasing the chances of blood coagulating in the legs, ultimately causing irregularities like DVT and PE.
- Compression of blood vessels
- The expanding uterus can compress the major blood vessels, such as the inferior vena cava, reducing the blood flow from the lower body to the heart. This can lead to irregularities in the bloodstream causing the blood to clot.
- Hypercoagulability
- Owing to the natural protective system, the blood thickens during pregnancy. However, this adds complications to the list as well. Clotting can cause serious issues during pregnancy.
- Certain pre-existing conditions
- Some women may have pre-existing conditions that increase the risk of blood clots, such as inherited clotting disorders, autoimmune disorders, or heart conditions. These conditions can elevate during pregnancy, further increasing the risk.
The Risk Factor

- Increased risk of bleeding
- Blood thinners reduce clots, but they also increase the risk of bleeding. Bleeding during pregnancy can cause complications.
- If the bleeding continues, it can pose more significant risks to the expectant mother and the fetus growing.
- Risk to the fetus
- The role of blood thinners in heart disease is crucial for managing and preventing complications. If you are to consume blood thinners during your pregnancy, then recurrent monitoring is a must to ensure optimal health and safety.
- This can add to the risk of bleeding in the fetus and invite several other complications. However, this depends entirely on the thinners you are prescribed.
- Limited safety data
- The amount of data you may find around you regarding blood thinners and their usage in pregnancy is relatively less. This lack of data can harm and put two lives in danger.
- It is advisable not to stop taking any medication before consulting your healthcare provider.
- Monitoring requirements
- If you are to consume blood thinners during your pregnancy, then recurrent monitoring is a must.
- You need to regularly monitor the effects of the thinner and see to it that no clots are found.
The Positive Pros

- Prevention of blood clots
- The main aim of consuming thinners is to prevent blood clotting, which is quite essential during pregnancy. Pregnant women have a high chance of incurring DVT and PE.
- Thinners reduce the viscosity of blood, eventually easing its flow.
- Management of certain medical conditions
- Conditions like certain clotting disorders, previous history of blood clots, certain autoimmune disorders, and certain heart conditions are kept in check with the help of blood thinners.
- These thinners can also aid in pregnancy by managing these conditions and reducing the risk of complications.
- Reduction of complications
- Preventing blood clots, blood thinners can potentially reduce the risk of complications associated with clotting disorders.
- If you are on blood thinners, you are on a low-risk spectrum of illnesses such as miscarriage, stillbirth, placental abruption (the separation of the placenta from the uterus), and intrauterine growth restriction (poor fetal growth).
The Bottom Line
Pregnancy is the time when you need to take utmost care of yourself as an expecting mother, especially if you have preexisting health conditions. Blood thinners are a lifesaver, but you must be aware of the merits and demerits while you are in such an important phase of your life. You must discuss the usage and dosage of the medication with your healthcare provider before jumping to conclusions.
Frequently Asked Questions
Are blood thinners safe during pregnancy?
Blood thinning is generally safe, but several precautions are necessary during pregnancy. While some thinners can cause pregnancy complications and harm the fetus’s development, you should consult your healthcare provider before changing the medication or stopping abruptly.
What is the preferred blood thinner in pregnancy?
LMWH is the preferred anticoagulant for pregnant women. Neither LMWHs nor UFH cross the placenta and are safe for the fetus. LMWH carries a lower risk of osteoporosis and heparin-induced thrombocytopenia (HIT) and is preferred for pregnant women.
Where do you inject blood thinners when pregnant?
You must inject onto the side of your stomach at least 5cm (2 inches) away from your belly button or any scars. It is important to change where you inject each time. You must pull off the needle cap and be careful not to bend the needle.