Preventing venous thromboembolism during pregnancy and postpartum: crossing the threshold

Abstract

When should a patient with a known thrombophilia or prior venous thromboembolism (VTE) receive low-molecular-weight heparin (LMWH) prophylaxis during pregnancy and/or the postpartum period? Accurately predicting thrombotic and bleeding risks and knowing what to do with this information is at the heart of decision-making in these challenging scenarios. This article will explore the concept of a risk threshold from clinician and patient perspectives and provide guidance for the use of antepartum and postpartum LMWH prophylaxis in women with a known thrombophilia or prior VTE. Advice for the management of LMWH prophylaxis use around labor and delivery is also reviewed.

Planned induction versus spontaneous delivery among women using prophylactic anticoagulation therapy: a retrospective study

“…19 However, others have supported induction of labour due to the potential risks of missing the opportunity to have neuraxial analgesia, and the occurrence of increased bleeding during labour. 10,11 This controversy highlights the need for evidence-based data in order to provide women with adequate counselling. In the current cohort, 88.5% of the women who were admitted following spontaneous onset of labour were eligible for neuraxial analgesia (i.e.…”

“…6,9 Nevertheless, for women using prophylactic LMWH therapy, there is a lack of consensus as to whether scheduled delivery following a minimum of 12 hours off anticoagulation would affect the chance of having neuraxial analgesia or result in improved maternal outcomes compared with allowing spontaneous onset of delivery. [10][11][12] Given the paucity of literature, we aimed to evaluate the role of planned induction of labour, compared with spontaneous onset of labour, among women using prophylactic LMWH therapy.…”

Prevention of Venous Thromboembolism during Pregnancy and the Puerperium with a Special Focus on Women with Hereditary Thrombophilia or Prior VTE—Position Paper of the Working Group in Women's Health of the Society of Thrombosis and Haemostasis (GTH)

“…30 In general, women with a PC and PS deficiency and no prior and family history of VTE seem to have a risk for VTE of <1% in the antepartum and postpartum periods. 31 The risk of the rare AT deficiency is difficult to predict and varies according to the subtype of deficiency. Individuals with quantitative defects (type I) or reactive site or pleiotropic mutations (types IIa and IIc) display a significantly increased risk of VTE compared with individuals with mutations of the heparin-binding site (type IIb).…”

“…54,55 In contrast, a systematic review reported a case fatality rate for pregnancy-associated VTE of 0.7%. 56 Therefore, it has been argued that pharmacologic prophylaxis has to prevent at least two to three more VTE events to be considered safe and beneficial 31 .…”

“…65,66 Thus, a substantial reduction in activity levels (e.g., AT < 60%, PC < 50% and free PS < 40%) is associated with a substantial increase in the VTE risk. 26,31 It is important to note that PS activity levels decrease physiologically with ongoing pregnancy, so that a reliable diagnosis of PS deficiency during pregnancy is not possible. PS testing should therefore be performed outside of pregnancy and at the earliest 8 to 12 weeks after delivery.…”