The Royal College of Obstetricians and Gynaecologists (RCOG) is updating its current Green-top Guidance 37a: Reducing the Risk of Venous Thromboembolism During Pregnancy and the Puerperium; this is being led by the 37a guideline developer team.
This update will bring the guidance in line with NHS England's Maternal Care Bundle (MCB) and align it with the latest published evidence base.
Pregnancy and the postpartum period are associated with a significantly increased risk of venous thromboembolism (VTE). According to recent MBRRACE-UK reports, thrombosis and thromboembolism remain the leading direct cause of maternal death in the UK during pregnancy and up to six weeks postpartum.
While the updated guidance is in development, the College has published a position statement (interim clinical guidance) that clarifies:
- Women in the first trimester (or the first antenatal booking appointment), or those who experience a miscarriage or termination, should be offered care according to NHS England's Maternal Care Bundle.
- After the first antenatal booking appointment - including labour, birth and the six weeks after birth - clinicians should continue to follow current RCOG guidance, but apply key changes:
- A revised VTE risk assessment
- Updated weight-based LMWH dosing
- A new threshold offering thromboprophylaxis for women with a BMI ≥50 kg/m², throughout pregnancy and for six weeks postpartum
Dr Jenny Barber, Vice President for Clinical Quality at the RCOG said:
"Thrombosis and thromboembolism are serious but often preventable. This makes early identification and management of women at increased risk in pregnancy essential.
"We are committed to supporting our members through updated guidance that gives clinicians clear, evidence-based recommendations.
"While this work is under way, we urge clinicians to refer to this statement, which clarifies how the College's existing guidance complements NHS England’s Maternity Care Bundle."
Kate Duhig, National Specialty Advisor for Obstetrics and Prevention at NHS England, said:
“The NHS’ maternal care bundle was developed to tackle inequalities and reduce maternal mortality and morbidity across England, including providing rapid access to thromboprophylaxis for those identified at high risk.
“The Royal College of Obstetricians and Gynaecologists has been a key partner in developing these new best practice standards, so we really welcome their updated guidance to provide clarity and consistency to professionals managing the risk of venous thromboembolism in the women they care for.”
The updated version of Green-top Guidance 37a is expected to publish in Spring 2027.
- We encourage all clinicians to access the full statement with details of the changes here: Reducing the Risk of Thrombosis and Embolism during Pregnancy and the Puerperium (Green-top Guideline No. 37a) | RCOG
- Access our patient information resource on reducing the risk of venous thrombosis in pregnancy here: Reducing the risk of venous thrombosis in pregnancy and after birth | RCOG
- The Guidance team at the RCOG is available to clarify any queries on this update: clinicaleffectiveness@rcog.org.uk