11 October 2016


Women are four times more likely to suffer postpartum venous thromboembolism after a caesarean section compared to a vaginal birth, new Swiss analysis has revealed.
A new study published in CHEST systematically reviewed 60 authoritative studies related to postpartum VTE outcomes, which found that there is a link between having a caesarean section and an increased absolute risk of VTE, including pulmonary embolism and deep vein thrombosis. An emergency caesarean had the greatest risk.
Dr Marc Blondon, lead investigator who works at the Division of Angiology and Haemostasis, Geneva University Hospitals, Geneva, said the risks were largely independent of other factors such as maternal age and body mass index.
 “We found that caesarean section is an important independent risk factor for the development of VTE in the postpartum period and that approximately three VTE will occur for every 1,000 caesarean sections performed, with greater risks for non-scheduled emergency caesarean section,” he said.
Pregnant women are more susceptible to VTE due in part to venous stasis and trauma associated with delivery, as well as haemostatic changes driving increases in some coagulation factors and decreasing bleeding inhibitors.
However, these changes are worse for women who have a C-section.
“In the postpartum period specifically, women following caesarean section exhibit greater activation of coagulation than women following vaginal delivery, as reflected by greater D-dimer levels,” said Dr Blondon.
 “This outcome may be a result of the conditions leading to the CS or to the procedure itself, similar to the increased VTE risk following non-obstetric surgery.
“Furthermore, physical activity is reduced following caesarean section compared with following vaginal delivery, with delayed recovery of mobility occurring in the first two days following delivery.”
While many non-obstetric surgical procedures employ thromboprophylaxis to minimise risk, researchers found little evidence of thromboprophylaxis being used after a C-section. In the USA, for example, it is prescribed just 25% of the time after C-sections.
“It is estimated that 75% of women following C-section do not receive any prophylaxis in the postpartum period. This scenario may arise from a lack of recognition by care providers of the risk of VTE following C-section,” said Dr Blondon.
“Preventing postpartum VTE following C-section may lead to an important reduction of its associated morbidity and mortality from a public health perspective.
“In this setting, further observational studies and randomised trials are needed to better appreciate the risks of VTE in specific groups following CS and to define the efficacy and safety of thromboprophylaxis.”
Blondon M, Casini A, Hoppe K et al. Risks of Venous Thromboembolism After Cesarean Sections: A Meta-Analysis.CHEST 3 September 2016.  
Link: http://dx.doi.org/10.1016/j.chest.2016.05.021
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