1. Introduction
Thromboembolism in pregnancy is among the leading causes of maternal
morbidity and mortality, worldwide [1-4]. In pregnant women, venous
thromboembolism (VTE) presents as deep vein thrombosis (DVT) or
pulmonary embolism (PE). It is well recognized that pregnancy increases
the risk of thromboembolism under conditions of hypercoagulability,
decreased mobility, and compression of the inferior vena cava and pelvic
veins. In recent decades, VTE has become a leading cause of sudden
death, accounting for 15-30% of all maternal deaths in the United
States and other Western countries [5-6]. Therefore, VTE in
pregnancy is an emerging health issue, and there is an urgent need to
estimate its prevalence profile.
The reported incidence of thromboembolism in pregnancy greatly varies.
Across different hospital settings, the rate of VTE diagnosis ranged
from 1 in 500 to 2,000 pregnancies in the United States [7-8].
Hospital organizational factors such as VTE prevention, diagnosis and
treatment potentially affect the disease’s incidence in pregnant women.
With the use of proper preventive mechanical prophylactic devices and
anticoagulants for high-risk pregnant women, the rate of maternal death
due to thromboembolic disease had declined from 14.8% in 2006 to 3.2%
in 2014 [9-10]. Additionally, considering the fact that there is an
overlap between the symptoms of VTE and pregnancy, the early detection
of VTE and the method used for the same influence the related diagnoses.
Second, the incidence of VTE varies across different patient
backgrounds: Asian women show a lower risk of VTE and death from VTE
than black women in the United States [11-12]. Third, the incidence
values varied across different epidemiological studies. In a
retrospective case-control study in United Kingdom, the incidence of VTE
was 0.85 per 1000 pregnancies [13], while in a population-based
cohort study in the United States, the incidence was 2 per 1000
pregnancies [14]. Thus, the incidence of VTE in pregnancy is
influenced by hospital-related variations due to differences in the
healthcare settings, diagnosis competency, and patient heterogeneity.
Given the marked diversity of hospital settings across China, we
hypothesize that the incidence of thromboembolism in pregnancy
significantly varies in different hospitals. In order to investigate the
status of VTE in China, and identify hospital organizational factors
affecting its incidence, we performed a hospital-based point prevalence
survey in 113 hospitals throughout China.