Association Between Maternal Weight Gain in Different Periods of
Pregnancy and the Risk of Venous Thromboembolism: A Retrospective
Matched Case-Control Study
Abstract
Objective To explore the incidence of pregnancy-related VTE in China and
to assess the associations of maternal weight gain in different periods
of pregnancy with VTE. Design Retrospective case-control study. Setting
Shanghai, China Participants 151 cases (11.7 per 10000) of
pregnancy-related venous thromboembolism (VTE) and 302 controls. Methods
GWG was standardized into gestational age-specific z-scores stratified
by body mass index (BMI) and categorized as low (< -1), normal
(-1 to 1), and high (>1). The adjusted odds ratios (aORs)
and 95% confidence intervals (CIs) were estimated through log-binomial
regression models. Main outcome measures Pregnancy-related VTE Results
There were 65.6% of pulmonary embolus (PE) and 34.4% of deep venous
thrombosis (DVT) alone or combined with PE. Among normal-weight women,
there was observed protective effects of low weight gain (aOR 0.79; 95%
CI 0.37–1.68) and significantly increased risks of high weight gain
(aOR=1.47; 95% CI: 1.03-2.09) for PE in early pregnancy. Similarly, a
tendency towards decreased risk at lower weight gain throughout
pregnancy (aOR 0.79; 95% CI 0.37–1.68) and significantly increased
risk at higher values (aOR=1.52; 95% CI: 1.01-2.31) for PE was
observed. As for underweight and overweight women, results from the
categorical model for early, late or total pregnancy weight gain
indicated an increased risk in PE at both low and high weight gain, but
confidence intervals were wide. Conclusion Maternal weight gain in total
or early pregnancy is an important risk factor for PE. Intensive weight
management that continues through pregnancy may be indispensable to
effectively improve pregnant outcomes.