Thromb Haemost 2011; 106(02): 304-309
DOI: 10.1160/TH10-12-0823
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Venous thromboembolism in pregnant and puerperal women in Denmark 1995–2005

A national cohort study
Rie Adser Virkus
1  Department of Obstetrics and Gynaecology, Hillerød Hospital, University of Copenhagen, Hillerød, Denmark
,
Ellen Christine Leth Løkkegaard
1  Department of Obstetrics and Gynaecology, Hillerød Hospital, University of Copenhagen, Hillerød, Denmark
,
Thomas Bergholt
1  Department of Obstetrics and Gynaecology, Hillerød Hospital, University of Copenhagen, Hillerød, Denmark
,
Ulla Mogensen
2  Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark
,
Jens Langhoff-Roos
3  Department of Obstetrics, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
,
øjvind Lidegaard
4  Gynaecological Clinic 4232, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
› Author Affiliations
Further Information

Publication History

Received: 29 December 2010

Accepted after major revision: 06 April 2011

Publication Date:
25 November 2017 (online)

Summary

Venous thromboembolism (VTE) is the leading cause of maternal death in the Western world, and the risk increases during pregnancy and puerperal period. It was the objective of the present study to estimate the absolute and the relative risk of VTE at different weeks of gestation and in the postnatal period as compared to non-pregnant women. This was a historical controlled national cohort study. The National Registry of Patients identified relevant diagnoses. These data were linked to The National Registry of Medical Products Statistics for information about current use of oral contraceptives. Danish women 15 to 49 years old during the period January 1995 through December 2005 were included in the study. In total 819,751 pregnant women were identified of whom 727 had a diagnosis of VTE. The absolute risk of VTE per 10,000 pregnancy-years increased from 4.1 (95% CI, 3.2 to 5.2) during week 1–11 up to 59.0 (95% CI: 46.1 to 76.4) in week 40 and decreased in the puerperal period from 60.0 (95% CI:47.2–76.4) during the first week after birth to 2.1 (95% CI:1.1 to 4.2) during week 9–12 after birth. Compared with non-pregnant women, the incidence rate ratio rose from 1.5 (95% CI:1.1 to1.9) in week 1–11, to 21.0 (95%CI16.7 to 27.4) in week 40 and 21.5 (95% CI:16.8 to 27.6) in the first week after delivery, declining to 3.8 (95% CI:2.5 to 5.8) 5–6 weeks after delivery. In conclusion, the risk of VTE increases almost exponentially through pregnancy and reaches maximum just after delivery and is no longer significantly increased six weeks after delivery.