Contraceptive Failure Rates of Etonogestrel Subdermal Implants in Overweight and Obese Women

Abstract

Objective To estimate the contraceptive failure rates of the etonogestrel subdermal contraceptive implant in overweight and obese women, and compare failure rates to women of normal weight and women using intrauterine devices (IUDs). Methods The Contraceptive CHOICE Project is a large prospective cohort study designed to promote the use of long-acting reversible contraceptive methods to reduce unintended pregnancies in the St. Louis region. Participants are provided reversible contraception of their choice at no cost. We collected baseline height and weight of each participant. During each survey, participants were asked about missed menses and possible pregnancies. Any participant who suspected a pregnancy was asked to come in for urine pregnancy testing. Analysis includes the first 8,445 participants enrolled in CHOICE of which 1,168 chose the implant and 4,200 chose the IUD. Student’s t-test, χ2 test, and Kaplan-Meier survival curves were used to perform statistical analyses to estimate failure rates in overweight and obese women using the implant and IUDs. Results Of the women choosing the implant, 28% were overweight and 35% were obese. Of the women who chose an IUD, 27% were overweight and 35% were obese. The 3-year cumulative failure rates for implant and IUD users were less than 1 per 100 women-years and did not vary by body mass index (BMI). Conclusion We found no decrease in the effectiveness of the implant in overweight or obese women. The implant may be offered as a first-line contraceptive method to any woman seeking a reversible, and reliable birth control method.

The US etonogestrel implant mandatory clinical training and active monitoring programs: 6-year experience

“…A cohort study with 1168 etonogestrel implant users showed that the effectiveness of the implant did not decrease in overweight or obese women [17]. A recent pharmacokinetic study also demonstrated no significant differences in etonogestrel concentrations between normal-weight and obese women over time, consistent with the clinical effectiveness data [18].…”

Contraception for Adolescents

“…58 Systematic reviews and large cohort studies have revealed no or mixed effects for the effect of both body weight and BMI on COCs, IUDs, implants, and contraceptive injections. [238][239][240] When examining complications, the World Health Organization and CDC found that among adult women, COC users with obesity are more likely than nonusers to experience thromboembolic complications. 111 However, the absolute risk of thromboembolic complications among adolescent COC users is low.…”

Contraception for Adolescents

“…117,118 The World Health Organization and CDC report that data are limited and inconsistent about whether COC effectiveness varies by body weight or BMI. 37,[150][151][152] A common concern of both adolescents and providers is additional weight gain among adolescents with obesity after they start contraception. Data suggest that women with obesity are no more likely to gain weight with COCs, the vaginal ring, IUDs, or implants than normalweight peers.…”