Optimization of an integrated traditional Chinese and western medicine regimen for thin endometrium using motherwort injection combined with different doses of CPET - evaluating endometrial receptivity and clinical pregnancy outcomes.

OBJECTIVE: Thin endometrium (TE) is an important factor associated with embryo implantation failure and adverse pregnancy outcomes during assisted reproductive treatment. This study investigated the clinical efficacy of fixed-dose motherwort injection (MI) combined with different doses of compound estradiol/dydrogesterone tablets (CPET) in the treatment of TE, evaluated its effects on endometrial receptivity, and determined the optimal therapeutic dose of CPET. METHODS: A retrospective propensity score-matched cohort study was conducted. Patients with TE treated between August 2024 and October 2025 were included. After 1:1:1 PSM, patients were matched into a control group, a low-dose CPET group, and a high-dose CPET group, with 58 patients in each group. The control group received MI alone, whereas the low- and high-dose CPET groups received different doses of CPET in addition to MI. The intervention lasted for three consecutive cycles. Endometrial morphology and hemodynamic parameters were assessed by transvaginal ultrasonography. Serum sex hormones and cytokines were measured by ELISA, and peripheral-blood mRNA expression of receptivity-related genes was detected by qPCR as an exploratory systemic molecular marker. Clinical pregnancy outcomes, safety, and cost-effectiveness were also analyzed. RESULTS: After treatment, all three groups showed improvements in endometrial thickness, endometrial volume, the proportion of type A endometrium, and blood perfusion. The high-dose group exhibited the greatest improvement, followed by the low-dose group and the control group. In the high-dose group, serum VEGF, IGF-1, and LIF levels increased, whereas TGF-β1 levels decreased; meanwhile, peripheral-blood mRNA expression levels of ITGAV, ITGB3, HOXA10, SPP1, and KDR increased in a dose-dependent manner (P<0.05), providing exploratory transcriptional evidence rather than direct confirmation of protein expression in endometrial tissues or signaling pathway activation. The clinical pregnancy rate and live birth rate in the high-dose group reached 51.7% and 44.8%, respectively, both higher than those in the control group. No significant differences were observed in early or late miscarriage rates among the three groups (P>0.05). Adverse reactions were mainly mild, and the overall incidence of adverse reactions did not differ significantly among groups (P>0.05). The high-dose group also showed a more favorable cost-effectiveness profile. CONCLUSION: MI combined with low- or high-dose CPET may improve endometrial receptivity and pregnancy outcomes in patients with TE. In this retrospective cohort, the high-dose regimen showed favorable short-term efficacy, tolerability, and cost-effectiveness. However, further studies using endometrial tissue samples are required to verify protein-level changes and the specific signaling pathways underlying the observed clinical effects.