(485) Anticoagulation preventive therapy versus no therapy and the risk for venous thromboembolism during the postpartum

Thursday, January 30, 2025

4:00 PM – 6:00 PM

Submitting Author and Presenting Author(s)

Enav Yefet, MD, PhD

Tzafon Medical Center
Poriya, HaZafon, Israel

Coauthor(s)

SH

Sally Hosari Mahamed, MD

Emek medical center
Afula, HaZafon, Israel
YS

Yael Skinez, MD

Emek medical center
Afula, HaZafon, Israel
ZN

Zohar Nachum, MD, MHA

Emak Medical Center
Afula, HaZafon, Israel

Objective: Until 2011, enoxaparin was given for postpartum venous thromboembolism (VTE) prophylaxis in women with thrombophilia or previous VTE (pre-protocol). Since 2012, VTE prophylaxis protocol was implemented and enoxaparin was given also to women with risk factors according to the RCOG. We aimed to compare the efficacy and safety of enoxaparin treatment postpartum before and after protocol implementation.

Study Design: Retrospective cohort study was conducted at Emek medical center in Israel. One delivery per woman was chosen randomly. The study included two periods; the pre-protocol period between 2003 and 2011 (N=19,783), and the protocol period from 2012 to 2020 (N=20520). Enoxaparin was administered for 6 weeks in case of thrombophilia or past VTE and 7-10 days in case of other risk factors. The primary outcome was the rate of VTE. Secondary outcomes were bleeding complications. Assuming that the protocol will reduce the rate for VTE from 1:1000 to 1:4000, 34,860 women were required (5% 2-sided alpha, 80% power).

Results: Patients' characteristics and outcomes are presented in the table. In the pre-protocol period, 531 women (2.7%) were treated with enoxaparin in the postpartum period. After protocol implementation, 964 (4.7%) women were treated due to known thrombophilia or past VTE event (P < 0.0001). Another 6.5% of the women received enoxaparin due to risk factors. The rate of VTE events in the postpartum period was 3 (0.02%) and 4 (0.02%) cases before and after the protocol implementation, respectively, (P=1). Postpartum bleeding complications were comparable between the before and after protocol implementation groups, including postpartum hemorrhage (16 (0.08%) vs. 24 (0.12%), respectively, P=0.25) or the need for blood transfusions (2 (0.01%) vs. 5 (0.02%), respectively, P=0.45).

Conclusion: Protocol for postpartum VTE prophylaxis according to risk factors with enoxaparin treatment did not lower the rate of VTE events, which are rare to begin with. The guidelines for postpartum VTE prophylaxis should be re-evaluated.