Table 1

Study and population characteristics

Author, yearCountryDesignSingle/ multicentreSample sizePopulationPeriodMean age (years)VTE prophylaxisRAMs evaluatedTarget condition, definition (risk period)Incidence
Antepartum and postpartum following vaginal and caesarean delivery
Bauersachs et al, 200723GermanyP, NRSMulti810Women at increased risk of VTE (due to thromboembolic status and prior VTE)March 1999 to December 200230.8100%

  • EThIG

Antepartum and postpartum VTE, symptomatic (NR)0.62%
(antepartum: 0.25%; postpartum: 0.37%)
Chauleur et al, 200827FranceP, CSSingle2685All women who deliveredJuly 2002 to June 2003NR
(median, 29)		NR

  • STRATHEGE

Antepartum and postpartum VTE (NR)0.34%
(antepartum: 0.19%; postpartum: 0.15%)
Dargaud et al, 201728FranceP, CSSingle445Women at increased risk of VTE (due to thromboembolic status and prior VTE)January 2005 to January 201533100%

  • Lyon

Antepartum and postpartum VTE, not defined (pregnancy and 3 months postpartum)1.35%
Dargaud et al, 200529FranceR, CSSingle116Women at increased risk of VTE (due to thromboembolic status and prior VTE)2001 to 20033453%

  • Lyon

Antepartum and postpartum VTE, not defined (NR)0.86%
(antepartum only)
Hase et al, 201831BrazilP, CSSingle52Hospitalised pregnant women with cancer1 December 2014 to 31 July 20163157.7%

  • RCOG (modified)

Antepartum and postpartum VTE, not defined (pregnancy and 3 months postpartum)Unable to estimate—no VTE
Shacaluga and Rayment, 2019 (correspondence)34WalesR, CSSingle42 000All managed pregnancies2009 to 2015NRNR

  • All Wales

  • RCOG

Antepartum and postpartum VTE, not defined (NR)0.08%
(antepartum: 0.04%; postpartum: 0.04%)
Testa et al, 201536ItalyP, CSSingle1719All pregnant women enrolled in Pregnancy Healthcare ProgramJanuary 2008 to December 2010NR
(median 33)		4.6%

  • Novel (Testa)

Antepartum and postpartum VTE (NR)Unable to estimate—no VTE
Weiss and Bernstein, 200038USACCSingle19 cases: 57 control*Women with (confirmed cases) and without (unmatched control) VTE1987 to 1998NRNR

  • Novel (Weiss)

Antepartum and postpartum VTE, not defined (pregnancy and 6 weeks postpartum)–
Postpartum only following vaginal and caesarean delivery
Chau et al, 201926FranceR, CSSingle1069
(time period
2012: 557;
2015: 512)		All women who deliveredFebruary to April 2012 and February to April 20152012: 29
2015: 29		NR

  • Novel (Chau)

Postpartum VTE, not defined (8 weeks)2012: 0.18%
2015: 0.20%
Ellis-Kahana et al, 202039 †USAR, CSMulti83 500All obese women (BMI >30 kg/m2) who delivered2002 to 200827.8NR

  • Novel (Ellis-Kahana)

Postpartum VTE (NR)0.13%
Gassmann et al, 202130SwitzerlandR, CS‡Single344All women who delivered1–31 January 201932.224%

  • RCOG

  • ACOG

  • ACCP

  • ASH

Postpartum VTE, not defined (3 months)Unable to estimate—no VTE
Lindqvist et al, 200832SwedenCCSingle37 cases: 2384 controlAll women with (confirmed cases) and without (unselected population-based control) VTE1990 to 2005NRNR

  • SFOG (Swedish guidelines)

Postpartum VTE (NR)–
Sultan et al, 201635England (derivation)§ and, Sweden (validation)R, CSMulti662 387 (validation cohort)§All women (with no history of VTE) who delivered1 July 2005 to 31 December 201130.323%

  • Novel (Sultan)

  • RCOG§

  • SFOG (Swedish Guidelines)

Postpartum VTE
(6 weeks)		0.08%
(validation cohort)
Tran et al, 201937USAR, CSSingle6094All women who delivered after 14 weeks01 January 2015 to 31 December 2016NRNR

  • RCOG

  • Padua

  • Caprini

Postpartum VTE (6 months)0.05%
Postpartum following caesarean delivery
Binstock and Larkin, 2019 (abstract)24USAR, CSSingle2875Postpartum women following CD2011NRNR

  • Novel (Binstock)

  • RCOG

Postpartum VTE, not defined (NR)0.38%
Cavazza et al, 201225ItalyP, CSSingle501Postpartum women following CD2007 to 20093453.5%

  • Novel (Cavazza)

Postpartum VTE, symptomatic, not defined (90 days)0.20%
Lok et al, 201933Hong KongP, CSSingle859Postpartum women following CDMay 2017 to April 201832.93.3%

  • Novel (Lok)

  • RCOG

  • ACOG

Postpartum VTE, symptomatic, not defined (NR)Unable to estimate—no VTE

  • *Retrospective case–control study of pregnant and postpartum women, but data reported for antepartum period only due to low number of postpartum VTE events (n=2).

  • †Internal validation study (ie, prediction model development without external validation).

  • ‡Prospective cohort study with retrospective analysis, thus classified as retrospective cohort study.

  • §RCOG was applied to an English derivation cohort, n=433 353, incidence, 0.07% (312 events).

  • ACCP, American College of Chest Physicians; ACOG, American College of Obstetricians and Gynecologists; ASH, American Society of Hematology; BMI, body mass index; CC, case–control; CD, caesarean delivery; CS, cohort study; EThIG, Efficacy of Thromboprophylaxis as an Intervention during Gravidity Investigators; NR, not reported; NRS, non-randomised study; P, prospective; R, retrospective; RAM, risk assessment model; RCOG, Royal College of Obstetricians and Gynaecologists; SFOG, Swedish Society of Obstetrics and Gynecology; VTE, venous thromboembolism.