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Reducing the risk of venous thrombosis in pregnancy and after birth

Published: 06/08/2015

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, so it is important to see your midwife early in pregnancy.

This leaflet covers:

  • Why a DVT is serious
  • Risk factors for DVT and a pulmonary embolism (PE) before, during and after pregnancy
  • When your risk will be assessed
  • How to reduce the risk
  • Heparin treatment
  • What you should do when labour starts
  • What happens after birth
  • Breastfeeding if you are receiving treatment after birth

This information is based on the RCOG clinical guideline Reducing the Risk of Thrombosis and Embolism during Pregnancy and the Puerperium.

Elsewhere on the site

Treatment of venous thrombosis in pregnancy and after birth
Our patient information leaflet on treatment of venous thrombosis will be helpful if you've already had a venous thrombosis during pregnancy or after birth.

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