OC 52.5 - Superficial venous thrombosis of the lower extremities during pregnancy and post partum: a Danish population-based cohort study

Tuesday, July 12, 2022

11:45 AM – 12:00 PM

Location: ExCel Center, S11B

Presentation Format: In-Person

Presenting Author(s)

Hanke M. Wiegers, MD

PhD Researcher
Department of Obstetrics and Gynaecology, University Medical Centers Amsterdam, University of Amsterdam, Amsterdam, Netherlands
Amsterdam, Noord-Holland, Netherlands

Co-Author(s)

DK

Dóra Körmendiné Farkas

MSc
Department of Clinical Epidemiology, Aarhus University Hospital,
Denmark, Midtjylland, Denmark
EH

Erzsébet Horváth-Puhó

Associate professor, MSc, PhD
Department of Clinical Epidemiology, Aarhus University Hospital,
Aarhus, Midtjylland, Denmark
Saskia Middeldorp, MD PhD

Professor
Department of Internal Medicine, Radboud university medical center, Nijmegen, The Netherlands
Nijmegen, Gelderland, Netherlands
Nick van Es, MD PhD

MD
Department of Vascular Medicine, Amsterdam University Medical Center, Amsterdam, The Netherlands
Amsterdam, Noord-Holland, Netherlands
HT

Henrik Toft Sørensen

MD, Professor,
Department of Clinical Epidemiology, Aarhus University Hospital,
Aarhus, Midtjylland, Denmark

Background: Data on the risk of lower extremity superficial venous thrombosis (SVT) during pregnancy and the postpartum period are lacking.

Aims: To examine: 1) the incidence rate of lower extremity SVT during pregnancy and in the postpartum period and 2) the risk of subsequent venous thromboembolism (VTE) within the same pregnancy.

Methods: This nationwide population-based cohort study of all deliveries between 1997 and 2017 in Denmark was based on two nationwide health registries: the Danish National Patient Registry and the Medical Birth Registry covering all Danish hospitals and deliveries. Incidence rates per 1000 person-years were calculated overall and separately per trimester and the postpartum period. Furthermore, the risk of VTE within the same pregnancy and postpartum period after a pregnancy-related SVT was calculated compared to an age- and parity matched pregnant comparison cohort without previous SVT. Sensitivity analyses were performed on first pregnancies and on women without a history of VTE.

Results: A total of 1,276,046 deliveries in 733,951 women were included in this study. 710 SVT events occurred from conception up to 12 weeks post partum, yielding an overall incidence rate of 0.58 (95%CI, 0.54–0.63) per 1000 person years. The incidence rates of SVT per 1000 person-years during the first, second, and third trimester were 0.13 (95%CI, 0.09-0.18), 0.24 (95%CI, 0.19-0.29), and 0.54 (95%CI, 0.46-0.62), respectively; the incidence rate was 1.69 (95%CI, 1.54-1.84) per 1000 person-years during the postpartum period. In 10.4% of pregnancies with SVT, a VTE occurred during the antepartum or postpartum period, compared with 0.13% of pregnancies without SVT. Sensitivity analyses attenuated the results.

Conclusion(s): We found a low incidence rate of lower extremity SVT during pregnancy and post partum. However, if SVT during pregnancy occurs the risk to develop VTE within the same pregnancy is high. These results may inform decisions about anticoagulant management after pregnancy-related SVT.