Pre Insertion and Post Insertion of Mirena Effect on Uterine Artery and Sub Endometrial Plexus Doppler Indices

Background: The levonorgestrel-releasing intrauterine system (Mirena) is widely used for contraception and management of heavy menstrual bleeding. Its effects on uterine artery (UA) and subendometrial vascular Doppler indices remain clinically relevant for understanding its mechanism and predicting treatment response. Objectives: To evaluate the impact of Mirena insertion on UA and subendometrial Doppler indices before insertion and after 1 and 3 months in women with and without heavy menstrual bleeding. Methods: This case–control study was conducted on 36 multiparous women aged 20–40 years. Eighteen women with heavy menstrual bleeding (case group) were compared with 18 asymptomatic women (control group). Uterine artery pulsatility index (PI), resistance index (RI), and subendometrial PI, RI, vascularization index (VI), and flow index (FI) were assessed via transvaginal Doppler before Mirena insertion, and at 1- and 3-months post-insertion. Results: Uterine artery PI was significantly lower in cases than controls at baseline (1.35 ± 0.27 vs 2.21 ± 0.28, p<0.001) and remained lower at 1 month (1.32 ± 0.26 vs 2.14 ± 0.32) and 3 months (1.35 ± 0.30 vs 2.18 ± 0.28). A similar pattern was observed for UA RI (baseline 0.58 ± 0.08 vs 0.76 ± 0.07, p<0.001). Subendometrial PI, RI, VI, and FI all showed significantly higher vascularity in cases at all time points; however, none of the Doppler parameters demonstrated significant longitudinal change after Mirena insertion in either group (p > 0.05). Conclusions: Women with heavy menstrual bleeding exhibit persistently lower uterine artery impedance and higher subendometrial vascularity compared with controls. Mirena insertion does not significantly alter Doppler indices within the first 3 months.