Weight Gain with Hormonal Contraceptives
All three contraceptive methods—levonorgestrel IUD, Nexplanon (etonogestrel implant), and NuvaRing (etonogestrel vaginal ring)—can cause modest weight gain, with Nexplanon showing the most consistent evidence of weight increase (mean 2.8-3.7 pounds over 1-2 years), while levonorgestrel IUDs cause minimal to no weight gain, and NuvaRing has limited specific data but weight gain is listed as a common adverse effect.
Evidence by Method
Nexplanon (Etonogestrel Implant)
The FDA label for Nexplanon explicitly documents weight gain in clinical trials, reporting mean increases of 2.8 pounds at one year and 3.7 pounds at two years 1. Importantly, 2.3% of users removed the implant specifically due to weight concerns 1.
Recent high-quality research confirms these findings:
A 2021 cohort study of 1,024 adolescents and young adults found that weight gain occurred both before and after implant insertion at similar rates, suggesting the implant does not accelerate pre-existing weight gain trajectories 2. However, patients who specifically removed the implant for weight concerns did gain significantly more weight (65.5% gained ≥5% body weight) 2.
The 2021 ECHO trial (7,829 women across 4 African countries) demonstrated that etonogestrel implant users gained a mean of 2.4 kg over 12-18 months, which was significantly more than copper IUD users (1.5 kg) but less than DMPA users (3.5 kg) 3.
A 2018 multicenter randomized trial found etonogestrel implant users gained 3.0 kg over 36 months, comparable to levonorgestrel implant users but significantly more than IUD users (1.1 kg) 4.
Levonorgestrel IUD
The 2024 CDC guidelines note that weight measurement is not required before IUD insertion because obesity is not a contraindication, and they suggest baseline weight measurement only for future comparison if patients have concerns 5. This implies weight gain is not a major clinical concern with levonorgestrel IUDs.
Research evidence supports minimal weight impact:
The ECHO trial showed levonorgestrel implant users gained 2.4 kg over 12-18 months 3, though this refers to the implant formulation, not the IUD.
A 2019 study comparing levonorgestrel and etonogestrel implants found levonorgestrel implant users gained significantly more weight (3.16 kg) than etonogestrel users (0.77 kg) at 12 months 6, though again this is implant data.
Important caveat: Most weight data for levonorgestrel comes from implant studies, not IUD studies. The levonorgestrel IUD delivers much lower systemic hormone levels than implants, so weight gain is likely minimal to negligible.
NuvaRing (Etonogestrel Vaginal Ring)
The FDA label lists weight gain as occurring in 5-14% of users in clinical trials 7. Weight gain was also cited as a reason for discontinuation in 1-2.5% of users 7.
However, specific quantitative data on weight change with NuvaRing is limited. A 1997 study of a different contraceptive vaginal ring formulation (norethindrone acetate, not etonogestrel) mentioned weight gain as a side effect but provided no specific measurements 8.
Clinical Context and Counseling Points
Key Considerations:
Baseline weight matters: The 2018 multicenter trial found that implant users weighing >50 kg gained significantly more weight than IUD users in the same weight category 4. Women with obesity may be at higher risk for weight gain with progestin-only methods.
Individual variation is substantial: While mean weight gains are modest (2-4 kg over 1-3 years), some individuals experience clinically significant weight gain while others lose weight. Standard deviations in studies are large (4-7 kg) 2, 3, 4.
Weight gain occurs over time regardless of contraception: The 2021 adolescent study showed weight gain trajectories were similar before and after implant insertion, suggesting natural weight gain in this population 2.
French endocrinology guidelines state there is no evidence that combined hormonal contraception causes weight gain in obese women 9, though this applies to combined methods, not progestin-only methods.
Practical Approach:
Measure baseline weight at contraceptive initiation for future comparison, as recommended by CDC guidelines 5
Counsel patients that:
- Nexplanon: Expect 3-4 pounds over 1-2 years on average
- Levonorgestrel IUD: Minimal to no weight gain expected
- NuvaRing: Weight gain reported in 5-14% of users, but specific amounts unclear
For patients highly concerned about weight: Consider copper IUD (non-hormonal) as it showed the least weight gain in comparative trials (1.1-1.5 kg over 12-36 months) 3, 4
Monitor weight at follow-up visits and address concerns proactively, as weight-related discontinuation undermines contraceptive efficacy
Recognize that patients who discontinue specifically for weight gain do tend to gain more weight than those who continue 2, suggesting some individuals are genuinely more susceptible to this side effect