Efficacy of low-intensity focused ultrasound on endometrial regeneration after surgical abortion: a multicentre...

Low-intensity focused ultrasound (LIFU) has been shown to effectively enhance postpartum uterine involution and may facilitate endometrial regeneration. The study aimed to evaluate the therapeutic efficacy and safety of LIFU for endometrial regeneration after surgical abortion. We conducted a prospective multicentre randomised controlled trial in 14 clinical centres in China. 421 eligible participants at 6-10 gestational weeks seeking surgical abortion, randomly allocating 210 to the LIFU group and 211 to the control group. Participants in LIFU group received LIFU treatment for 30 min per day for 5 consecutive days plus routine post-abortion care, whereas control group received routine care alone. Endometrial thickness (mm), assessed by transvaginal ultrasound on postoperative days 21-25, was predefined as the primary outcome. 349 women (180 LIFU, 169 control) completed the trial. Both intention-to-treat (ITT) and per-protocol set (PPS) analyses were performed. The ITT analysis revealed significantly greater endometrial thickness in the LIFU group (8.23 ± 2.32 mm) compared to controls (7.54 ± 2.18 mm) at postoperative days 21-25 (P = 0.005). Adjustment for covariate confirmed this effect (β = 0.65 mm, P = 0.003). Multivariate analysis indicated inverse association between preoperative gestational sac diameter and endometrial recovery (β = -0.06 per 1 mm increase, P = 0.010), while total uterine diameter exhibited a positive association (β = 0.09 per 1 cm increase, P = 0.015). No LIFU-related adverse events occurred during the three-month postabortion follow-up. This trial demonstrates that LIFU is an effective and well-tolerated non-pharmacological intervention to enhance endometrial recovery after surgical abortion. ChiCTR2300068608. Dated 24/2/2023 prospectively registered. (https://www.chictr.org.cn/showproj.html?proj=189346).