Introduction
Deep vein thrombosis (DVT) and pulmonary embolism (PE) are collectively
referred to as venous thromboembolic disease (VTE). Although the rate of
maternal mortality has declined over the past few decades, PE remains an
important cause of maternal deaths[1,2]. During
pregnancy, a women’s risk of VTE is increased by 6 times, with reported
incidence ranging from 0.5 to 2.0 per 1000
deliveries[3,4]. Approximately 75–80% of cases
of pregnancy-associated VTE are caused by DVT, and 20–25% of cases are
caused by PE[5]. However, few studies have
examined trends in the incidence of pregnancy-related VTE in China.
Several studies have already identified risk factors for
pregnancy-related VTE, including advanced maternal age, greater body
mass index (BMI), cesarean delivery, preeclampsia, postpartum hemorrhage
and newborns with low birth weight[1,6-11]. They
help care providers to target the use of thromboprophylaxis to women at
risk to maximize its benefit[12]. However, few
studies have evaluated gestational weight gain (GWG) as a risk factor
for VTE[13]. Although insufficient and excessive
maternal weight gain has been linked with increased risks of
VTE[13], they have often not accounted for the
effects of weight gain during certain periods of pregnancy. Furthermore,
the
associations of specific periods of GWG with detailed PE and DVT has not
been reported. In addition, few studies have examined trends in the
incidence of pregnancy-related VTE in China, and these studies have
shown variable results[14,15].
For this retrospective case–control study of women, our objective was
to explore the incidence of pregnancy-related VTE in China, and evaluate
the association of maternal weight gain in different periods of
pregnancy with detailed pulmonary embolism (PE) and deep vein thrombosis
(DVT).