Blood Clot Risk During Pregnancy (DVT)
Medically reviewed by Dr. Lisa Okafor, MD, FACOG · Board-Certified OB-GYN
Content reviewed against published ACOG, NIH, CDC guidelines
Last reviewed:
Your health matters just as much as your baby's. If you are dealing with blood clot risk during pregnancy (dvt), here is what you need to know.
The short answer
Pregnancy increases the risk of blood clots (venous thromboembolism or VTE) by 4-5 times due to increased clotting factors, slower blood flow, and vein compression from the growing uterus. While the overall risk is still low (about 1-2 per 1,000 pregnancies), awareness of symptoms is important because blood clots can be life-threatening if untreated.
Key takeaways
- Pregnancy increases the risk of blood clots (venous thromboembolism or VTE) by 4-5 times due to increased clotting factors, slower blood flow, and vein compression from the growing uterus. While the overall risk is still low (about 1-2 per 1,000 pregnancies), awareness of symptoms is important because blood clots can be life-threatening if untreated.
- Usually normal when: Mild bilateral (both legs) swelling in late pregnancy is normal and is not a clot sign
- Call your doctor if: Swelling, pain, warmth, or redness in ONE leg (especially the calf) that is different from the other leg - possible DVT
- Varies by age — see the age-by-age breakdown below
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What Parents Should Know
According to ACOG, NIH, CDC guidelines, pregnancy increases the risk of blood clots (venous thromboembolism or VTE) by 4-5 times due to increased clotting factors, slower blood flow, and vein compression from the growing uterus. While the overall risk is still low (about 1-2 per 1,000 pregnancies), awareness of symptoms is important because blood clots can be life-threatening if untreated. At First trimester, blood clot risk is elevated from early pregnancy. Risk factors include previous blood clots, family history, obesity, immobility, cesarean delivery, and certain genetic clotting disorders. If you have risk factors, your provider may recommend blood thinners (low-molecular-weight heparin). Stay active and hydrated. It is generally considered normal when mild bilateral (both legs) swelling in late pregnancy is normal and is not a clot sign. However, you should contact your pediatrician promptly if swelling, pain, warmth, or redness in ONE leg (especially the calf) that is different from the other leg - possible DVT.
Normal vs. Concerning
By Age
What to expect by age
First trimester
Blood clot risk is elevated from early pregnancy. Risk factors include previous blood clots, family history, obesity, immobility, cesarean delivery, and certain genetic clotting disorders. If you have risk factors, your provider may recommend blood thinners (low-molecular-weight heparin). Stay active and hydrated.
Third trimester
Risk increases as the uterus puts maximum pressure on pelvic veins. Avoid sitting or standing for long periods. On long car or plane trips, move regularly and stay hydrated. Compression stockings can help. Be aware of DVT symptoms: swelling, pain, warmth, and redness in one leg (usually the calf).
Postpartum
Blood clot risk is highest in the first 6 weeks after delivery, especially after cesarean. Get moving as soon as safely possible after delivery. Your provider may recommend compression stockings or blood thinners if you have additional risk factors. VTE is a leading cause of maternal mortality, making awareness critical.
What to Tell Your Pediatrician
- Describe when you first noticed blood clot risk during pregnancy (dvt) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if you have a personal or family history of blood clots or clotting disorders.
- Mention if you will be immobile for extended periods (bed rest, long travel).
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
What Should You Do?
When to take action
- Mild bilateral (both legs) swelling in late pregnancy is normal and is not a clot sign
- Varicose veins without warmth, redness, or pain are common and not typically a clot
- You have a personal or family history of blood clots or clotting disorders
- You will be immobile for extended periods (bed rest, long travel)
- You have multiple risk factors for blood clots
- Swelling, pain, warmth, or redness in ONE leg (especially the calf) that is different from the other leg - possible DVT
- Sudden shortness of breath, chest pain, rapid heartbeat, or coughing up blood - possible pulmonary embolism - call 911 immediately
- These are medical emergencies that require immediate evaluation
What You Can Do at Home
- Keep track of when you notice blood clot risk during pregnancy (dvt) — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that mild bilateral (both legs) swelling in late pregnancy is normal and is not a clot sign — this is generally within the range of normal.
- At First trimester, focus on observation rather than intervention unless your pediatrician advises otherwise.
- Prioritize your own rest and nutrition. Accept help when offered, and do not hesitate to reach out to your healthcare provider.
- While monitoring at home, seek immediate care if swelling, pain, warmth, or redness in ONE leg (especially the calf) that is different from the other leg - possible DVT.
Related Conditions
Varicose Veins in Pregnancy
Varicose veins are swollen, twisted veins that commonly appear in the legs during pregnancy. They affect up to 40% of pregnant people and are caused by increased blood volume, hormonal changes that relax vein walls, and pressure from the growing uterus on pelvic veins. They are usually a cosmetic concern but can cause aching or discomfort.
Swelling in Feet, Ankles, and Hands During Pregnancy
Mild to moderate swelling (edema) in the feet, ankles, and hands is very common in pregnancy, affecting about 80% of pregnant people. It is caused by increased blood volume and fluid retention, and it is usually harmless. However, sudden or severe swelling, especially in the face and hands, can be a warning sign of preeclampsia.
Air Travel While Pregnant
Air travel is generally safe for most pregnant people through 36 weeks of pregnancy (earlier for international flights or some airlines). The cabin pressure, altitude, and radiation exposure on commercial flights do not pose risks to healthy pregnancies. The main concern is the increased risk of blood clots from prolonged sitting, which can be mitigated by walking, stretching, and staying hydrated.
Related Resources
Postpartum Recovery Guide
Week-by-week postpartum recovery timeline and warning signs.
Month-by-Month Development
Detailed monthly development guides from birth through 24 months.
When to Call the Doctor
General guide on when to call the pediatrician, visit urgent care, or go to the ER.
Frequently asked questions
Is blood clot risk during pregnancy (dvt) normal?
When should I call the doctor about blood clot risk during pregnancy (dvt)?
When is blood clot risk during pregnancy (dvt) normal?
What causes blood clot risk during pregnancy (dvt)?
What should I mention to my pediatrician about blood clot risk during pregnancy (dvt)?
Is blood clot risk during pregnancy (dvt) normal at First trimester?
Is blood clot risk during pregnancy (dvt) normal at Third trimester?
Should I go to the ER for blood clot risk during pregnancy (dvt)?
Does blood clot risk during pregnancy (dvt) go away on its own?
References
- [1]American College of Obstetricians and Gynecologists. Thromboembolism in Pregnancy. ACOG Practice Bulletin No. 196, 2018. ACOG
- [2]National Library of Medicine. Venous Thromboembolism in Pregnancy. StatPearls, 2023. NIH
- [3]Centers for Disease Control and Prevention. Blood Clots During Pregnancy. CDC, 2023. CDC
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss Blood Clot Risk During Pregnancy (DVT).
Things to mention
- Describe when you first noticed blood clot risk during pregnancy (dvt) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if you have a personal or family history of blood clots or clotting disorders.
- Mention if you will be immobile for extended periods (bed rest, long travel).
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- You have a personal or family history of blood clots or clotting disorders
- You will be immobile for extended periods (bed rest, long travel)
- You have multiple risk factors for blood clots
Urgent signs to report immediately
- Swelling, pain, warmth, or redness in ONE leg (especially the calf) that is different from the other leg - possible DVT
- Sudden shortness of breath, chest pain, rapid heartbeat, or coughing up blood - possible pulmonary embolism - call 911 immediately
- These are medical emergencies that require immediate evaluation
My notes
From ismybabyalright.com — free, evidence-based baby health guides
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members
Related Resources
Bottom line
Most cases of blood clot risk during pregnancy (dvt) are normal. Talk to your pediatrician if swelling, pain, warmth, or redness in one leg (especially the calf) that is different from the other leg - possible dvt.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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Related Maternal Concerns
Varicose Veins in Pregnancy
Varicose veins are swollen, twisted veins that commonly appear in the legs during pregnancy. They affect up to 40% of pregnant people and are caused by increased blood volume, hormonal changes that relax vein walls, and pressure from the growing uterus on pelvic veins. They are usually a cosmetic concern but can cause aching or discomfort.
Swelling in Feet, Ankles, and Hands During Pregnancy
Mild to moderate swelling (edema) in the feet, ankles, and hands is very common in pregnancy, affecting about 80% of pregnant people. It is caused by increased blood volume and fluid retention, and it is usually harmless. However, sudden or severe swelling, especially in the face and hands, can be a warning sign of preeclampsia.
Air Travel While Pregnant
Air travel is generally safe for most pregnant people through 36 weeks of pregnancy (earlier for international flights or some airlines). The cabin pressure, altitude, and radiation exposure on commercial flights do not pose risks to healthy pregnancies. The main concern is the increased risk of blood clots from prolonged sitting, which can be mitigated by walking, stretching, and staying hydrated.
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