The Impact of Body Mass Index on Bleeding Pattern in Women Discontinuing Usage of a Subdermal Contraceptive Implant [34I

Abstract

INTRODUCTION: The etonogestrel subdermal contraceptive implant is among the most effective contraceptive methods available. The most common associated side effect is irregular menstrual bleeding. Approximately 15% of users discontinue implant usage prematurely due to unacceptable bleeding. Understanding of how obesity impacts the side effect profile of the implant is limited, since the initial clinical trials excluded obese patients. However, recent studies have suggested that obese patients are less likely report irregular or heavy bleeding than are their normal-weight counterparts, although these studies were small and examined predominately white patients. We sought to study whether BMI impacted the bleeding pattern of implant users in our large, racially diverse population. METHODS: This study was deemed exempt from the UT Austin IRB. We conducted a chart review of patients in Austin’s CommUnity Care clinic system who had an implant removed between 2012 and 2017. For each subject, we abstracted age, race/ethnicity, gravidity/parity, BMI, and indication for implant discontinuation. Univariate analysis was conducted to determine whether the reason for implant discontinuation varied between underweight, normal-weight, overweight, and obese patients. RESULTS: Data were abstracted for 636 subjects. 40% of normal-weight subjects discontinued usage of a contraceptive implant due to irregular bleeding, compared to 55% of underweight and 26% of obese subjects. Duration of implant usage did not vary between BMI classes. CONCLUSION: Underweight women were more likely to discontinue implant usage due to irregular bleeding than normal-weight women, and obese women were less likely to do so. This may guide counseling regarding expected bleeding pattern for prospective implant users.