Incidence of VTE in Pregnant Women with Sickle Cell Gene Mutation(s): A Retrospective Database Analysis

Purpose/Objective(s): The leading cause of pregnancy-associated mortality in Western countries is venous thromboembolism (VTE) with an absolute incidence of 0.025 to 0.1 percent in the general pregnant population. Noubiap et al reported that sickle cell disease (SCD) patients had a significantly higher risk for VTE (pooled OR 4.4, 95%CI 2.6-7.5, p < 0.001), deep vein thrombosis (DVT) (OR 1.1, 95% CI 1.1-1.2, p < 0.001) and pulmonary embolism (PE) (pooled OR 3.7, 95% CI 3.6-3.8, p < 0.001) as compared to patients without SCD [1]. Although sickle cell trait (SCT) and SCD have an increased risk for VTE, the incidence of VTE during pregnancy has not been documented. Our primary objective was to record a composite incidence of VTE among pregnant patients with SCT/SCD.

Material/Methods: A retrospective, cross-sectional analysis including pregnant patients with SCT and SCD was conducted at our tertiary care academic medical center. Data was collected between January 2011 and December 2020. Adult women up to 51 years old with hemoglobin electrophoresis proven SCT and SCD were included. Risk factors for VTE such as the patient's body mass index (BMI), COVID status, family history of VTE, and smoking history were included in the analysis. ANOVA and Chi-square tests were used for analysis and to calculate a composite incidence, odds ratio, confidence interval, and p-value. A p-value of <0.05 was considered statistically significant. Data was analyzed using the SAS system.

Results: A total of 139 pregnant SCT/SCD patients were included for analysis, out of which, the majority of the patients were SCT (84/139, 60.4%). The mean age at pregnancy was 26.42 (standard deviation 5.72). The type of VTE included DVT 58.3% (14/24) and PE 41.7% (10/24). At our facility, the incidence rate of VTE in pregnancy for SCT/SCD was 17% as compared to 0.025 to 0.1% in the general population. There was no statistically significant difference in the odds of developing VTE between SCD and SCT (OR= 1.09, 95% CI [.45, 2.63]). Only 2.16% of patients had positive COVID infection, as most of the collected data predated the pandemic. Almost one-third of the patients were smokers (45/139) and only 2.88% (4/139) had a family history of VTE. BMI was divided into BMI <30 (38.13%, 53/139) and BMI >30 (61.87%, 86/139). Obesity (OR= 1.03, 95% CI [.4166, 2.56]) and COVID status (OR=2.45, 95% CI [.21, 28.23]) were not found to be significant in our population of patients. Patients with a family history of DVT had a greater odd of developing VTE (OR=50.70, 95% CI [2.63, 977.88]), although the sample may not provide a precise representation of the population mean.

Conclusion: Currently, ASH guidelines recommend a conservative approach to VTE prophylaxis unless research suggests benefits [2]. Our analysis found a 17% incidence of pregnancy-associated VTE in our SCT/SCD patients, which is drastically higher than the general population. With such a significant increased incidence in this patient population, especially with current racial disparities in African American maternal mortality rates, more research should be conducted to evaluate the need for thromboprophylaxis/treatment. Additionally, evaluation for specific SCT/SCD guidelines and recommendations to decrease pregnancy-related VTE and mortality rates should be discussed.

Master:Cardinal Health: Membership on an entity's Board of Directors or advisory committees; Aptitude health: Membership on an entity's Board of Directors or advisory committees; curio sciences: Membership on an entity's Board of Directors or advisory committees; Blue Bird Bio: Current holder of stock options in a privately-held company; Toxicity: Current holder of stock options in a privately-held company; Gilead: Current holder of stock options in a privately-held company; Jasper: Current holder of stock options in a privately-held company.