Association Between Obesity and Thrombosis During Pregnancy and the Postpartum Period: A Case-Control Study From a Tertiary Care Center in Kerala, India

Background Obesity is postulated to be a high-risk factor for thrombosis along with the inherent hypercoagulability of pregnancy. The Confidential Review of Maternal Deaths (CRMD) found that thrombosis was one of the major causes of maternal deaths in Kerala. This study investigates the major risk factor - obesity and its association with thrombosis in our study setting, along with other risk factors. Obesity, being a modifiable risk factor, can thus be targeted to decrease maternal morbidity and mortality for a better pregnancy outcome. This study sought to examine the association between obesity and thrombosis during pregnancy and the postpartum period in a tertiary care center in Kerala, India, while also identifying other risk factors that may contribute to thrombotic events in this population. Methodology A hospital-based case-control study was conducted at Government Medical College, Thiruvananthapuram, Kerala, India, from March 2017 to September 2018. The study population comprised 42 cases diagnosed with thrombotic events during pregnancy and the postpartum period, including deep vein thrombosis (DVT), cortical venous thrombosis (CVT), and pulmonary thromboembolism (PTE). Using consecutive sampling from the hospital's labor register, 84 controls were selected, maintaining a case-to-control ratio of 1:2. Detailed clinical information was collected through direct patient interviews and medical record reviews. Body mass index (BMI) was calculated using pre-pregnancy weight and height measurements. Variables assessed included demographic characteristics, obstetric history, socioeconomic status, blood group, gestational age at thrombosis, type and location of thrombosis, risk factors, comorbidities, clinical manifestations, treatment modalities, and outcomes. Results The study demonstrated a significant association between obesity and thrombotic events in pregnancy and postpartum periods. In the case group, 21 patients (50.0%) presented with Class I obesity, and three patients (7.1%) with Class II obesity. The control group included 14 patients (16.7%) with Class I obesity and no patients (0%) with Class II obesity, revealing a significant difference in BMI class distribution between groups (χ²=25.979, p<0.001). Among the cases, DVT was the predominant presentation in 29 patients (69.0%), primarily affecting the ileo-femoral region in 26 patients (61.9%). CVT occurred in 12 patients (28.6%). Of the DVT patients, obesity was present in 17 patients (58.6%) compared to 12 non-obese patients (41.4%), showing statistical significance (χ²=14.488, p=0.001). Additional significant risk factors were identified in the study group: period of immobility affected five patients (11.9%), puerperal infection was present in five patients (11.9%), and antiphospholipid antibodies (APLA) positivity was found in five patients (11.9%). All these risk factors showed statistically significant differences compared to controls (p=0.001). Treatment outcomes were favorable, with 40 patients (95.2%) achieving either complete resolution or showing improvement. Conclusion Obesity significantly increases pregnancy-associated thrombosis risk, particularly DVT in the ileo-femoral region. Additional factors like immobility, puerperal infection, and APLA positivity contribute to thrombosis development. While treatment outcomes are favorable, early recognition and management are crucial, especially in women with multiple risk factors.