Abstract: Objective To investigate the effects of the Mirena and dydrogesterone tablets on endometrial thickness, menstrual blood loss, hormone receptor levels, and recurrence in patients undergoing hysteroscopic polypectomy. Methods A total of 330 endometrial polyp (EP) patients who underwent hysteroscopic polypectomy at Haining People's Hospital from September 2021 to December 2023 were enrolled and randomly assigned to three groups using a random number table (n = 110 each): the Mirena group (levonorgestrelreleasing intrauterine system inserted postoperatively), the dydrogesterone group (oral dydrogesterone tablets postoperatively), and the control group (surgery only). Endometrial thickness, menstrual blood volume, hormone receptor levels, and recurrence rates were compared among the three groups. Results Compared with pre-treatment levels within the same group, endometrial thickness decreased at 1, 3, 6, and 12 months postoperatively in all three groups (P ＜ 0.001). Additionally, compared to 1 month postoperatively within the same group, endometrial thickness decreased further at 3, 6, and 12 months in all three groups (P ＜ 0.001). Similarly, decreases were observed at 6 and 12 months compared to 3 months postoperatively, and at 12 months compared to 6 months postoperatively within each group (P ＜ 0.001). No significant differences in endometrial thickness were found among the three groups before treatment and at 1 month postoperatively (P ＞ 0.05). However, at 3, 6, and 12 months postoperatively, endometrial thickness in both the Mirena and dydrogesterone groups was thinner than in the control group (P ＜ 0.001). There was no significant difference in endometrial thickness between the Mirena and dydrogesterone groups at any postoperative time point (1, 3, 6, 12 months) (P ＞ 0.05). Compared with pretreatment levels within the same group, menstrual blood volume decreased at 1, 3, 6, and 12 months postoperatively in all three groups (P ＜ 0.001). Sequential decreases were also observed at 3, 6, and 12 months compared to 1 month postoperatively, at 6 and 12 months compared to 3 months postoperatively, and at 12 months compared to 6 months postoperatively within each group (P ＜ 0.001). No significant differences in menstrual blood volume were found among the three groups before treatment and at 1 month postoperatively (P ＞ 0.05). At 3, 6, and 12 months postoperatively, menstrual blood volume in both the Mirena and dydrogesterone groups was less than in the control group (P ＜ 0.001). There was no significant difference in menstrual blood volume between the Mirena and dydrogesterone groups at any postoperative time point (P ＞ 0.05). Before treatment, there were no significant differences in the levels of estrogen receptor (ER) and progesterone receptor (PR) among the three groups (P ＞ 0.05). Compared to pre-treatment levels, ER and PR levels decreased at 6 and 12 months postoperatively in all three groups (P ＜ 0.001). At 6 and 12 months postoperatively, ER and PR levels in both the Mirena and dydrogesterone groups were lower than those in the control group (P ＜ 0.001). There were no significant differences in ER and PR levels between the Mirena and dydrogesterone groups at 6 and 12 months postoperatively (P ＞ 0.05). During the 12-month postoperative follow-up period, there was a significant difference in the recurrence rates among the three groups (χ² = 40.94, P ＜ 0.001). The recurrence rates in both the Mirena and dydrogesterone groups were lower than that in the control group (χ² = 32.637, 19.478 respectively, P ＜ 0.001). There was no significant difference in the recurrence rate between the Mirena and dydrogesterone groups (χ² = 2.379, P = 0.123). Conclusion Both the Mirena and dydrogesterone tablets can improve endometrial thickness, menstrual blood volume, and hormone receptor status, and reduce recurrence rates in patients with EP, demonstrating significant therapeutic advantages compared to hysteroscopic polypectomy alone.