Maternal obesity and venous thromboembolism.

The incidence of obesity in pregnancy has increased rapidly in the last decade. Obesity is a risk factor for venous thromboembolism outside of pregnancy and previous studies of maternal death in the UK have identified obesity as a risk factor in pregnancy. As a result the Royal College of Obstetricians and Gynaecologists have targeted obesity as a risk factor in evaluation of the need for thromboprophylaxis in pregnancy. This article highlights the evidence that obesity increases the risk of venous thromboembolism in pregnancy and the puerperium, discusses thromboprophylaxis and appropriate dosing in obese parturients and details the anaesthetic implications of the 2009 Royal College of Obstetricians and Gynaecologists' guidelines. More clinical studies are required to clarify the appropriate dose of low-molecular-weight heparin in an obese parturient.