Thrombosis is a blood clot in a blood vessel (a vein or an artery). Venous thrombosis occurs in a vein. Veins are the blood vessels that take blood towards the heart and lungs whereas arteries take the blood away. A deep vein thrombosis (DVT) is a blood clot that forms in a deep vein of the leg, calf or pelvis.
Pregnancy increases your risk of a DVT, with the highest risk being just after you have had your baby. However, venous thrombosis is still uncommon in pregnancy or in the first 6 weeks after birth, occurring in only 1–2 in 1000 women.
A DVT can occur at any time during your pregnancy, including the first 3 months.
This information leaflet covers:
- Why a DVT is serious
- Risk factors for DVT and a pulmonary embolism (PE) before, during and after pregnancy
- How DVT and PE are diagnosed during pregnancy
- Tests and any associated risks
- Treatment for DVT
- What you should do when labour starts
- What happens after birth
- Breastfeeding if you are receiving treatment after birth