Aim

To clarify the relation between institutions capacity to manage venous thromboembolism (VTE) and its incidence in pregnant women throughout Japan.

Methods

Among the 2299 institutions that received the surveillance questionnaire, 666 (29.0%) responded, after which data from 295 961 women who gave birth at those institutions in 2018 were analyzed. Incidences and characteristics of antepartum and postpartum VTE in perinatal medical centers (PMCs), general hospital with obstetric facilities (GHs), and maternal clinic with beds (MCs) were then determined.

Results

The frequencies at which routine antepartum and postpartum thromboprophylaxis for high-risk women and routine transport to the more advanced medical institutions upon antepartum and postpartum pulmonary thromboembolism (PE) onset were performed differed significantly according to types of institution (PMCs: 92.4%, 96.2%, 23.8%, and 21.2%; GHs: 76.5%, 80.6%, 58.8%, and 54.1%; MCs: 29.2%, 41.7%, 96.5%, and 96.2%, respectively). Among the 295 961 women analyzed, 243 (0.082%) developed VTE. Incidences of antepartum VTE differed significantly according to institution types (PMCs: 106.4, GHs: 51.6, and MCs: 11.6 per 100 000 women). PMCs and GHs had significantly higher incidences of postpartum VTE compared to MCs (43.3 and 26.6 vs. 10.7 per 100 000 women, respectively), although PMCs and GHs had similar incidences. Among the four women (1.4%) who died due to VTE, three and one developed a PE in a PMC and MC, respectively.

Conclusions

PMCs had higher incidences of VTE despite their more frequent performance of thromboprophylaxis. Several pregnant women with higher risk of VTE transported to PMCs.