Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH
Combined hormonal contraception and risk of venous thromboembolism within the first year following pregnancy
Danish nationwide historical cohort 1995–2009
Jesper Friis Petersen
1
Department of Gynecology and Obstetrics, Hillerød Hospital, Hillerød, University of Copenhagen, Denmark
,
Thomas Bergholt
1
Department of Gynecology and Obstetrics, Hillerød Hospital, Hillerød, University of Copenhagen, Denmark
,
Anne Kristine Nielsen
1
Department of Gynecology and Obstetrics, Hillerød Hospital, Hillerød, University of Copenhagen, Denmark
,
Michael J. Paidas
2
Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale Women and Children’s Center for Blood Disorders, Yale University School of Medicine, New Haven, Conneticut, USA
,
Ellen Christine L. Løkkegaard
1
Department of Gynecology and Obstetrics, Hillerød Hospital, Hillerød, University of Copenhagen, Denmark
› Author AffiliationsFinancial support: The study was funded by the research foundation at Hillerød Hospital. The funding organisation had no role in the study planning, data collection, analysis, writing of the article, or in the decision to submit the article for publication. All authors held positions independent from funding organisation.
Estimating the risk of venous thromboembolism (VTE) associated with combined hormonal contraceptives following early terminated pregnancies or birth, a Danish nationwide retrospective cohort observing a one-year follow-up was defined using three unique registries. All Danish women with confirmed pregnancies aged 15–49 during the period of 1995–2009 were included. The main outcomes were relative and absolute risks of first time venous thromboembolism in users as well as non-users of combined hormonal contraceptives. In 985,569 person-years, 598 venous thromboembolisms were recorded. After early terminated pregnancies and births, respectively, 113 and 485 events occurred in 212,552 and 773,017 person-years. After early terminated pregnancies, the crude VTE incidence ratios were similar, and the numbers needed to harm were equal between groups that did or did not use combined hormonal contraceptives throughout the follow-up year. After childbirth, individuals that used combined hormonal contraceptives were more likely than non-users to experience VTE depicted by crude incidence ratios; however, the difference was only significant after 14 weeks. This implied that the numbers needed to harm were lower for those that used compared to those that did not use combined oral contraceptives in the initial 14 weeks postpartum. In conclusion, the use of combined hormonal contraceptives after early terminated pregnancies was not detrimental, but during the puerperal period, they should be used with caution.
Keywords
Venous thromboembolism -
early termination of pregnancy -
birth -
puerperal period
References
1
Bodker B,
Hvidman L,
Weber T.
et al. Maternal deaths in Denmark 2002-2006. Acta Obstet Gynecol Scand 2009; 88: 556-562.
3
Cantwell R,
Clutton-Brock T,
Cooper G.
et al. Saving Mothers’ Lives: Reviewing maternal deaths to make motherhood safer: 2006-2008. The Eighth Report of the Confidential Enquiries into Maternal Deaths in the United Kingdom. Br J Obstet Gynaecol 2011; 118 (Suppl. 01) 1-203.
4
Manzoli L,
De Vito C,
Marzuillo C.
et al. Oral contraceptives and venous throm-boembolism: a systematic review and meta-analysis. Drug Saf 2012; 35: 191-205.
5
Jackson E,
Curtis KM,
Gaffield ME.
Risk of venous thromboembolism during the postpartum period: a systematic review. Obstet Gynecol 2011; 117: 691-703.
6
Update to CDC’s U.S..
Medical Eligibility Criteria for Contraceptive Use, 2010: revised recommendations for the use of contraceptive methods during the post-partum period. Morb Mortal Wkly Rep 2011; 60: 878-883.
7
Heit JA,
Kobbervig CE,
James AH.
et al. Trends in the incidence of venous thromboembolism during pregnancy or postpartum: a 30-year population-based study. Ann Intern Med 2005; 143: 697-706.
9
Salonen Ros H,
Lichtenstein P,
Bellocco R.
et al. Increased risks of circulatory diseases in late pregnancy and puerperium. Epidemiology 2001; 12: 456-460.
10
Virkus RA,
Lokkegaard EC,
Bergholt T.
et al. Venous thromboembolism in pregnant and puerperal women in Denmark 1995-2005. A national cohort study. Thromb Haemost 2011 106: 304-309.
11
Lidegaard O,
Lokkegaard E,
Svendsen AL.
et al. Hormonal contraception and risk of venous thromboembolism: national follow-up study. Br Med J 2009; 339: b2890.
12
Lidegaard O,
Nielsen LH,
Skovlund CW.
et al. Risk of venous thromboembolism from use of oral contraceptives containing different progestogens and oestrogen doses: Danish cohort study, 2001-9. Br Med J 2011; 343: d6423.
14
Sultan AA,
Tata LJ,
West J.
et al. Risk factors for first venous thromboembolism around pregnancy: a population-based cohort study from the United Kingdom. Blood 2013; 121: 3953-3961.
15
Larsen TB,
Johnsen SP,
Moller CI.
et al. A review of medical records and discharge summary data found moderate to high predictive values of discharge diagnoses of venous thromboembolism during pregnancy and postpartum. J Clin Epidemiol 2005; 58: 316-319.
