A-163 Elevated Serum Estradiol in Levonorgestrel-Releasing Intrauterine System Users: A Case Series Highlighting Post-Analytical Challenges
The levonorgestrel-releasing intrauterine system (LNG-IUS) acts predominantly at the endometrial level without consistently suppressing the hypothalamic–pituitary–gonadal axis. Residual ovarian activity may persist, occasionally resulting in functional follicular cysts capable of producing estradiol. Serum estrad...