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22-12-2011 | Cardiology | Article

VTE risk in pregnancy remains high after delivery


Free abstract

MedWire News: UK study results show that the increased risk for venous thromboembolism (VTE) associated with pregnancy is highest in the third trimester and remains elevated until 3 weeks postpartum.

"These findings should influence the development of updated thromboprophylaxis guidelines and impact the delivery of care to pregnant women across the developed world," say the authors in the British Journal of Haematology.

Based on their findings, Matthew Grainge (University of Nottingham) and colleagues recommend delaying the administration of thromboprophylaxis until the third trimester. This, they say, would avoid the side effects associated with prolonged thromboprophylaxis.

They add: "Our observation that the highest rates of VTE occur mainly within 3 weeks postpartum suggests that giving thromboprophylaxis in those considered at high risk for this length of time [after giving birth] may be appropriate."

The findings arise from the analysis of VTE rates among 972,683 women with no VTE history. All participants were aged 15-44 years and followed-up for a median of 6.4 years. Among these women, 207,327 live birth pregnancies occurred - equivalent to 145,380 person-years of antepartum time, 50,907 person-years of postpartum time, and 5,131,554 person-years of nonpregnancy time (at least 3 months after delivery).

VTE rates in the first and second trimester were up to twice as high as non-pregnancy VTE rates. In contrast, the risk for VTE during the third trimester of pregnancy was sixfold higher than outside of pregnancy.

Furthermore, postpartum VTE risk peaked at 3 weeks postpartum, with a VTE risk 22 times higher than that occurring outside of pregnancy.

Age was found to be an independent predictor for VTE risk in the postpartum and non-pregnancy periods only, with a 70% higher VTE risk among women aged 35 years or older compared with women aged 25-34 years in the postpartum or nonpregnancy period.

Grainge and team conclude: "Our findings are generalizable to the majority of pregnant women who have not had prior VTE, providing valuable information to accurately assess the risk for VTE and potential need for prophylaxis."

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Lauretta Ihonor

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