This study aims to evaluate and compare weight gain in reproductive-age women using long acting reversible contraception over 12, 36 and 60-month periods.
Retrospective cohort study of 36,584 female patients between 15 and 45 years old with either the LNG-IUS, ENG implant or copper IUD for at least 12 consecutive months between April 2008 and April 2017. A Kruskal-Wallis test was performed to compare the magnitude of weight gain at the specified time intervals. The influence of race and age were evaluated through multivariate linear regression. IRB approval was obtained.
After 12 months, copper IUD and LNG-IUS users lost weight (0.58 and 0.08 kg, respectively), while ENG implant users gained weight 1.15 kg (P<.01). After 36 months, copper IUD users gained 0.46 kg, LNG-IUS users gained 0.72 kg and ENG implant users gained 3.84 kg (P<.01). After 60 months, LNG-IUS users gained twice as much weight as copper IUD users (1.52 and 0.87 kg, respectively). Black and Hispanic women gained more weight than white and Asian women, especially in those younger than 35 years old. (P<.01).
At 12 and 36 months, ENG implant users demonstrated both statistically and clinically significant weight gain compared to LNG-IUS and copper IUD users. However, in the adjusted model, only ENG implant users younger than 35 demonstrated a significant weight gain. Race proved to be a predictor of weight gain. These observations may help counsel women towards an appropriate LARC method, taking into consideration age and race.