Previous studies have also shown the administration of estrogen alone and estrogen-containing oral contraceptives to users of subdermal levonorgestrel implants (Norplant®) resulted in decreased frequency of irregular uterine bleeding , . A prior randomized, controlled trial found a 0.1mg estradiol patch resulted in the clinical improvement of abnormal bleeding, however this finding was not statistically significant . A randomized, controlled trial of DMPA users found the cyclic administration of 0.1mg estradiol patches did not decreases irregular menstrual bleeding . In this study, the cyclic use of estrogen may have resulted in lower or inconsistent serum estradiol levels. Additionally, the progestational mechanism of action is more similar between levonorgestrel subdermal implants and LNG-IUC than depot medroxyprogesterone. No study has specifically addressed estrogen for treatment of irregular bleeding with the LNG-IUC.