Incidence and Risk Factors for Pregnancy-Associated Venous Thromboembolism: Are There Differences between East and West?

Venous thromboembolism (VTE) manifests as thrombus formation in deep vein usually in lower legs which subsequently embolizes to pulmonary artery causing pulmonary embolism and increased risk of morbidity and mortality.[1] Even in this journal there has been much interest in the epidemiology, prognosis, and risk factors for VTE, as well as the pathophysiological mechanisms underlying the propensity to develop this common condition.[2] [3] [4] [5] [6] [7]

Pregnancy is an important risk factor for VTE. Several previous studies reported the incidence of pregnancy-associated VTE (PA-VTE) for Western population.[8] [9] [10] [11] One population-based cohort study of Canadian Institute for Health Information showed that the incidence rate of PA-VTE was 12.1 cases of per 10,000 deliveries between year 1991 and 2006.[9] Another Denmark population registry revealed an incidence rate of 5 cases per 10,000 deliveries from year 1995 to 2005.[10] As for United States, the incidence rate of PA-VTE was 6.6 per 10,000 deliveries between year 2000 and 2018,[11] which increased from 4 per 10,000 deliveries (from year 1978 to 1996).[8] These studies were carried out in different populations using different databases with different timelines. Therefore, it may be difficult to clearly understand the time trends of the incidence of PA-VTE.

Data from South Korea provided important information about the incidence and time trend of PA-VTE for Asians.[12] [13] In the study by Jang et al, utilizing the Korean Health Insurance Review and Assessment Service database, they reported the incidence rate of PA-VTE as 0.82 case per 10,000 deliveries in the Korean population from year 2004 to 2008.[12] In this issue of Thrombosis and Haemostasis, Hwang and colleagues used the similar database and reported the incidence rate of PA-VTE as 2.62% per 10,000 deliveries during year 2014 to 2018 in the Korean population.[13] The incidence rate of the second study increased approximately 3.2 times higher than that in the first study. Since these two studies were based on the same dataset, increasing incidences of PA-VTE in the Korean population were well illustrated ([Fig. 1]). Furthermore, like overall VTE, the risk of PA-VTE was also higher for Asian population compared to non-Asians ([Fig. 1]).

Fig. 1 Incidences and risk factors of pregnancy-associated VTE in Eastern and Western populations. The data and information contained in this figure were based on previous studies.[8] [9] [10] [11] [12] [13] [15] [16] [17] BMI, body mass index; VTE, venous thromboembolism.

The trends about the increasing risk of PA-VTE may be related to more pregnancy in advanced maternal age in modern society and the recent progress in assisted reproductive technology to treat infertility resulting in two- to threefold increased risk of VTE compared to spontaneous pregnancy.[14] Reported risk factors for PA-VTE included multiparity, multifetal pregnancies, advancing maternal age, cesarean section, cardiac disease, delivery at gestational age of <36 weeks, a body mass index of ≥25, or more, and postpartum period.[15] [16] [17] These risk factors were not obviously different between Western and Eastern population ([Fig. 1]). An underlying hormonal pathophysiological basis is possible, given the well-recognized links of VTE to oral contraceptive pills.[18]

Despite a lower risk of PA-VTE in Asians, the risk is increasing. Obstetricians need to be aware of the risks of VTE especially for patients with clinical high-risk features. Indeed, a focus has been directed on patient and health care provider-reported outcomes to gleam more information on this condition.[19]

Publication History

Received: 24 April 2023

Accepted: 24 April 2023

Article published online:
05 June 2023

• References

• 1 Nicholson M, Chan N, Bhagirath V, Ginsberg J. Prevention of venous thromboembolism in 2020 and beyond. J Clin Med 2020; 9 (08) 2467
• 2 Rønnow Sand J, Troelsen FS, Nagy D. et al. Increased cancer risk in patients with kidney disease and venous thromboembolism: a population-based cohort study. Thromb Haemost 2022; (e-pub ahead of print). DOI: 10.1055/s-0042-1759879.
• 3 McBane Ii RD, Vlazny DT, Houghton D. et al. Survival implications of thrombus recurrence or bleeding in cancer patients receiving anticoagulation for venous thromboembolism treatment. Thromb Haemost 2023; 123 (05) 535-544
• 4 Wang J, Tan J, Hua L, Sheng Q, Huang X, Liu P. Genetic predisposition of both waist circumference and hip circumference increased the risk of venous thromboembolism. Thromb Haemost 2023; 123 (03) 347-361
• 5 Ma Z, Sun X, Zhang Y. et al. Risk of thromboembolic events in cancer patients treated with immune checkpoint inhibitors: a meta-analysis of randomized controlled trials. Thromb Haemost 2022; 122 (10) 1757-1766
• 6 Noumegni SR, Mansourati V, Tromeur C. et al. Risk factors of cardiovascular death after venous thromboembolism: results from a prospective cohort study. Thromb Haemost 2022; 122 (10) 1744-1756
• 7 Mahajan A, Brunson A, Eldredge J, White RH, Keegan THM, Wun T. Incidence and outcomes associated with 6,841 isolated distal deep vein thromboses in patients with 13 common cancers. Thromb Haemost 2022; 122 (08) 1407-1414
• 8 Gherman RB, Goodwin TM, Leung B, Byrne JD, Hethumumi R, Montoro M. Incidence, clinical characteristics, and timing of objectively diagnosed venous thromboembolism during pregnancy. Obstet Gynecol 1999; 94 (5, Pt 1): 730-734
• 9 Liu S, Rouleau J, Joseph KS. et al. Epidemiology of pregnancy-associated venous thromboembolism: a population-based study in Canada. J Obstet Gynaecol Can 2009; 31 (07) 611-620
• 10 Virkus RA, Løkkegaard EC, Bergholt T, Mogensen U, Langhoff-Roos J, Lidegaard Ø. Venous thromboembolism in pregnant and puerperal women in Denmark 1995-2005. A national cohort study. Thromb Haemost 2011; 106 (02) 304-309
• 11 Krenitsky N, Friedman AM, Yu K. et al. Trends in venous thromboembolism and associated risk factors during delivery hospitalizations from 2000 to 2018. Obstet Gynecol 2022; 139 (02) 223-234
• 12 Jang MJ, Bang SM, Oh D. Incidence of venous thromboembolism in Korea: from the Health Insurance Review and Assessment Service database. J Thromb Haemost 2011; 9 (01) 85-91
• 13 Hwang HG, Lee JH, Bang SM. Incidence of pregnancy-associated venous thromboembolism: second nationwide study. Thromb Haemost 2023; 123 (09) 906-912
• 14 Goualou M, Noumegni S, de Moreuil C. et al. Venous thromboembolism associated with assisted reproductive technology: a systematic review and meta-analysis. Thromb Haemost 2023; 123 (03) 283-294
• 15 Simpson EL, Lawrenson RA, Nightingale AL, Farmer RD. Venous thromboembolism in pregnancy and the puerperium: incidence and additional risk factors from a London perinatal database. BJOG 2001; 108 (01) 56-60
• 16 Ram S, Ram HS, Neuhof B, Shperling RB, Chodick G, Yogev Y. Venous thromboembolism during pregnancy: trends, incidence, and risk patterns in a large cohort population. Int J Gynaecol Obstet 2023; 160 (03) 962-968
• 17 Sha M, Chen S. Pregnancy-related venous thromboembolism in Wuhan, China 2010-2022: a case-control study. J Obstet Gynaecol Res 2023; 49 (06) 1532-1538
• 18 Gris JC, Bourguignon C, Bouvier S. et al. Pregnancy after combined oral contraceptive-associated venous thromboembolism: an international retrospective study of outcomes. Thromb Haemost 2022; 122 (10) 1779-1793
• 19 King A, Leider H, Herman D, Malinowski AK, D'Souza R. Patient- and health-care-provider-reported outcomes to consider in research on pregnancy-associated venous thromboembolism. Thromb Haemost 2021; 121 (09) 1228-1236