Tiao-Jing-Cu-Yun Acupuncture combined with estradiol in the treatment of patients with thin endometrium undergoing hormone replacement therapy for frozen embryo transfer: a randomized controlled trial

Objective To investigate the effect of Tiao-Jing-Cu-Yun Acupuncture on pregnancy outcomes in infertility patients with thin endometrium undergoing artificial cycle frozen–thawed embryo transfer (AC-FET). Methods A prospective, assessor-blinded randomized controlled design was employed. A total of 92 infertility patients with endometrial thickness <7 mm undergoing AC-FET at our hospital were enrolled and randomly assigned to two groups: the control group ( n = 45) received oral estradiol valerate-based hormone replacement therapy combined with sham acupuncture; the Intervention Group ( n = 47) received the same HRT regimen combined with Tiao-Jing-Cu-Yun Acupuncture administered every other day starting from menstrual cycle day 2–3 until the day before embryo transfer. The primary outcome measure was the clinical pregnancy rate. Secondary outcomes included the embryo implantation rate, early miscarriage rate, and changes in endometrial parameters assessed via transvaginal ultrasound before and after treatment, including endometrial thickness, volume, pattern classification, subendometrial blood flow grading, and hemodynamic parameters. Results Baseline characteristics were comparable between the two groups. After treatment, the Intervention Group showed a significantly greater increase in progesterone (P) level, endometrial thickness and volume, and a more pronounced decrease in endometrial resistance index (RI) and pulsatility index (PI) compared to the control group (all p < 0.05). Ultrasound assessment revealed that the proportion of patients achieving Pattern A endometrium and Grade III subendometrial blood flow after treatment was significantly higher in the Intervention Group than in the control group ( p < 0.05). Regarding pregnancy outcomes, the clinical pregnancy rate in the Intervention Group (55.32%) was significantly higher than that in the control group (31.11%), and the embryo implantation rate was also significantly increased (all p < 0.05). There was no statistically significant difference in the early miscarriage rate between the two groups ( p > 0.05). Conclusion The combination of Tiao-Jing-Cu-Yun Acupuncture with standard hormonal therapy can effectively improve endometrial receptivity in patients with thin endometrium and significantly enhance the clinical pregnancy success rate of frozen–thawed embryo transfer. Clinical Trial Registration https://itmctr.ccebtcm.org.cn/ , International Traditional Medicine Clinical Registry (ITMCTR), unique identifier: ITMCTR2026000585.