Scientific Poster Session III - Students Research-in-Progress

Students Research in Progress
  Monday, October 14, 2024
  01:00 PM–02:30 PM

Abstract

Introduction: In the U.S., the standard treatment for venous thromboembolism (VTE) in pregnant patients is enoxaparin 1 mg/kg subcutaneously twice daily. For obese non-pregnant patients (BMI =30 kg/m²), literature supports empiric dose reductions to 0.8 mg/kg twice daily. It is unclear if obese pregnant patients require empiric enoxaparin dose adjustments.

Research Question or Hypothesis: This study investigates whether obese pregnant patients (BMI =30 kg/m²) require empiric enoxaparin dose adjustments compared to non-obese pregnant patients (BMI <30 kg/m²).

Study Design: A single-center retrospective chart review of pregnant, biological females (=18 years) receiving therapeutic enoxaparin at their first appropriately timed anti-Xa level. Exclusions included pregnancies terminated or miscarried before the first anti-Xa level and use of prophylactic enoxaparin.

Methods: Of 121 patients identified, 74 met inclusion criteria. The primary endpoint compared initial anti-Xa levels between obese and non-obese patients using the Kruskal Wallis test. Secondary endpoints compared enoxaparin dose adjustments made after patients’ first anti-Xa check to BMI as well as to initial anti-Xa levels using student T-tests, odds ratios, and one-way ANOVA.

Results: Initial anti-Xa levels differed significantly between obese and non-obese patients (p=0.045). No significant difference in dose adjustments was found between BMI groups (p=0.067). Significant differences in dose adjustments (p<0.001) and mean BMI (p=0.030) were noted between subtherapeutic (anti-Xa <0.5 units/mL) and supratherapeutic (anti-Xa >1 units/ml) patients. Non-obese patients had lower odds of therapeutic anti-Xa levels (OR=0.832, 95% CI 0.331-2.087) and higher odds of subtherapeutic levels (OR=2.357, 95% CI 0.826-6.727). Obese patients were less likely to require dose adjustments (OR=0.630, 95% CI 0.243-1.635).

Conclusion: These data suggest obese pregnant patients receiving enoxaparin 1 mg/kg twice daily are likely to achieve therapeutic anti-Xa without dose adjustments upon treatment initiation. Non-obese patients were more prone to subtherapeutic anti-Xa levels necessitating dose adjustments and may benefit from anti-Xa monitoring after treatment initiation.

Presenting Author

Reagan McGinn PharmD Candidate 2026
University of Michigan Health - Michigan Medicine

Authors

Selena Beck PharmD Candidate 2025
University of Michigan Health - Michigan Medicine

Rikki-Leigh Gaudet PharmD, BCCCP
University of Michigan Health - Michigan Medicine

Kayla Popova PharmD
University of Michigan Health - Michigan Medicine