Position statement – September 2026
The Royal College of Obstetricians and Gynaecologists (RCOG) is currently updating Green-top Guideline (GTG) No. 37a Reducing the Risk of Venous Thromboembolism during Pregnancy and the Puerperium. This update is being led by the 37a guideline developer team.
Pending publication of the updated guideline, clinicians should follow the current GTG No. 37a, but with the amendments as set out below, which align with the NHS England Maternal Care Bundle (MCB). Clinicians should also follow the MCB recommendations relating to women in the first trimester of pregnancy and those who experience miscarriage or choose to end their pregnancy.
While the update is in progress, it is suggested clinicians in Wales, Scotland and Northern Ireland also follow the advice below.
The aim of this guideline is to provide advice, based on clinical evidence where available, regarding the prevention of venous thromboembolism (VTE) during pregnancy, birth and following delivery. For the diagnosis and management of acute VTE in pregnancy, please refer to Green-top Guideline No. 37b: Thrombosis and Embolism during Pregnancy and the Puerperium: Acute Management.
Version history
The first edition of this guideline was published in 2004 (as Thromboprophylaxis during Pregnancy, Labour and after Vaginal Delivery); the second edition was published in 2009 (as Reducing the Risk of Thrombosis and Embolism during Pregnancy and the Puerperium). This is the third edition of this guideline, published in April 2015; reviewed in 2018 – no update required; reviewed in 2020 – no update required; reviewed in 2022 – no update required; reviewed in 2024 – an update is in development.
Developer declaration of interests
Available on request.