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RCOG release: Revised guidelines on reducing the risk and treatment options for thromboembolic disease in pregnancy

News 13 April 2015

Advice on preventing and treating venous thromboembolism (VTE) during pregnancy, birth and following delivery is outlined in two new revised guidelines published today (13 April) by the RCOG and launched at the RCOG World Congress in Brisbane, Australia.

VTE refers to the formation of a clot within veins. This can occur anywhere in the venous system but the predominant sites are in the vessels of the leg (giving rise to deep vein thrombosis (DVT)) and in the lungs (resulting in a pulmonary embolism (PE)).

The Green-top Guidelines provide information, based on clinical evidence, to assist clinicians with both the prevention and treatment of VTE in pregnant women, a condition which remains the leading direct cause of maternal death in the UK.

VTE is uncommon in pregnancy or in the first 6 weeks postnatally and the absolute risk is around 1 in 1000 pregnancies. It can occur at any stage in pregnancy but the first 6 weeks following birth is the time of highest risk, with the risk increasing by 20-fold.

Risk factors include previous VTE or thrombophilia (a tendency to form blood clots), obesity, increased maternal age, immobility and long-distance travel, admission to hospital during pregnancy and other comorbidities such as heart disease, inflammatory bowel disease and pre-eclampsia.

Additional risk factors occurring during the first trimester of pregnancy include; hyperemesis gravidarum, ovarian hyperstimulation and IVF pregnancy. Caesarean section is also a risk factor.

The guidance emphasises that all women should undergo a thorough assessment for VTE in early pregnancy or pre-pregnancy and again intrapartum or immediately postpartum.

Any woman with risk factors should be considered for prophylactic low-molecular-weight-heparin (LMWH), an injection administered to thin the blood. The duration of treatment depends on the number of risk factors a woman has. It may be offered both antenatally and after the baby is born.

Additionally, women with previous VTE must be offered pre-pregnancy counselling and a prospective management plan for VTE should be made including appropriate treatment to be offered as early as possible and a careful history documented.

The guideline on treating VTE focuses on the acute management of the condition and highlights the signs and symptoms including; leg pain and swelling, lower abdominal pain, shortness of breath, chest pain, coughing blood and collapse.

Any woman presenting with signs and symptoms suggestive of VTE should be tested for the condition immediately and treatment with LMWH offered. All hospitals should have a protocol for the diagnosis of suspected VTE with the involvement of a multi-disciplinary team of obstetricians, radiologists, physicians and haematologists, states the guidance.

Professor Catherine Nelson-Piercy lead author of the guideline on preventing thromboembolism said:

“Venous thromboembolism is rare in pregnancy and with prompt recognition can be treated effectively. This guidance provides clinicians with accurate scientific-based guidance on the risk factors for VTE as well as how to prevent and treat the condition.

“It is vital that VTE is discussed with all women at risk and reasons for individual treatment recommendations must be explained.”

Dr Andrew Thomson, lead author of the guideline on treating thromboembolism and co-Chair of the RCOG Guidelines Committee said:

"Previous editions of these guidelines have been credited with a reduction in the number of women dying from thromboembolism during their pregnancy or in the postnatal period in the UK. Nonetheless, thromboembolism remains an important cause of maternal morbidity and mortality in our country.

“These updated guidelines provide new evidence on risk factors for thrombosis in pregnancy and strategies that should be employed to reduce the chances of a thrombosis occurring. Furthermore the guidelines provide updated information on the way women with a suspected thrombosis should be investigated and treated."


For further information, please contact the RCOG Media and PR team on +44 20 7772 6300 or email

View the Green-top Guideline Thrombosis and Embolism during Pregnancy and the Puerperium, Reducing the Risk (Green-top Guideline No. 37a).

This is the third edition of this guideline, first published in 2004 and revised in 2009.

View the Green-top Guideline Thrombosis and Embolism during Pregnancy and the Puerperium, the Acute Management of (Green-top Guideline No. 37b).

This is the third edition of this guideline. The first edition was published in 2001 and the second edition was published in February 2007 and reviewed in 2010.