Effect of Baseline Menstrual Bleeding Pattern on Copper Intrauterine Device Continuation

Abstract

Background Heavy menstrual bleeding is a leading cause of copper intrauterine device (IUD) discontinuation. Thus, women with heavy baseline menstrual bleeding may be at increased risk for early copper IUD discontinuation. Our objective was to assess if there was an association between baseline menstrual bleeding pattern prior to IUD insertion and discontinuation rate at 12 months among study participants who chose copper IUD at baseline.

Study Design We performed a secondary analysis of the Contraceptive CHOICE Project, a prospective observational cohort study of 9,256 women offered no cost contraception for 2-3 years. Included in our study were participants who chose copper IUD for contraception and for whom method continuation data at 12 months were available. Prior to contraception initiation, participants were asked to qualify their menstrual bleeding over the past year as: light, moderate, moderately heavy or heavy. Light bleeding corresponded to using 10 or fewer pads/tampons per period. Moderate, moderately heavy and heavy bleeding corresponded to 11-20 pads/tampons, 21-30 pads/tampons, and more than 30 pads/tampons per period, respectively. Subjects were then categorized into either a “heavy” baseline group (those reporting moderately heavy or heavy bleeding at baseline), or a “not heavy” group (those reporting light or moderate bleeding). The 12-month continuation rate for each group was then calculated using Kaplan-Meier survival function, and hazard ratio for risk of discontinuation was evaluated using a Cox proportional hazard model to determine if moderately heavy or heavy bleeding at baseline was associated with early discontinuation.

Results Of the 918 women meeting the inclusion criteria for this analysis, 165 were in the heavy baseline bleeding group, while 753 were in the not heavy bleeding group. The 12-month continuation rates for groups were similar: 80.2% (heavy) and 85.0% (not heavy; P=0.24). Patients reporting either moderately heavy or heavy baseline bleeding were not at increased risk for early discontinuation of copper IUD (hazard ratio 1.21, 95% CI 0.88, 1.66). Our sample size provided greater than 90% power to detect a clinically important difference of 15% (assuming 20% discontinuation rate in not heavy bleeding group and a 35% discontinuation rate in the heavy bleeding group).

Conclusions We did not find that women who reported baseline moderately heavy or heavy menstrual bleeding were at increased risk for early discontinuation. Thus, we do not believe that women with heavy menstrual bleeding should be discouraged from using this safe and highly-effective form of contraception.