Correlation between tongue and pulse indicators and the outcome of live birth in frozen-thawed embryo transfer

Objective To investigate the correlation between tongue and pulse indicators and the outcome of live birth in patients undergoing frozen-thawed embryo transfer (FET), as well as the association between these indicators and patients’ endocrine parameters. Methods This study was conducted at Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China, from March 8, 2021 to January 5, 2022. Patients undergoing FET were divided into live birth and non-live birth groups according to their live birth outcome. The differences between the endocrine parameters [basic follicle stimulating hormone (b FSH), basic luteinizing hormone (b LH), basic estradiol (b E2), basic progesterone (b P), basal endometrial thickness, follicle stimulating hormone (FSH) on endometrial transition day, luteinizing hormone (LH) on endometrial transition day, estradiol (E2) on endometrial transition day, progesterone (P) on endometrial transition day, and endometrial thickness on endometrial transition day] and the tongue and pulse indicators [tongue body (TB)-L, TB-a, TB-b, tongue coating (TC)-L, TC-a, TC-b, perAll, perPart, h1, h4, h5, t1, h1/t1, and h4/h1] of patients in the two groups were analyzed, with the correlation between these variables analyzed as well using Spearman’s correlation coefficient. Multivariate logistic regression was employed to identify the influential factors in the live birth prediction models across various datasets, including Model 1 consisting of endocrine indicators only, Model 2 solely consisting of tongue and pulse indicators, and Model 3 consisting of both tongue, pulse, and endocrine indicators, as well as to evaluate efficacy of the models derived from different datasets. Results This study included 78 patients in live birth group and 144 patients in non-live birth group. Compared with non-live birth group, live birth group exhibited higher levels of TB-L (P = 0.01) and TB-a (P = 0.04), while demonstrated lower levels of b FSH (P = 0.01), perAll (P = 0.04), and h4/h1 (P = 0.03). The Spearman’s correlation coefficient analysis revealed statistically significant correlation (P < 0.05) between TB-L, TB-b, TC-L, TC-b, perAll, perPart, h4, h5, t1, h1/t1 and b FSH, b LH, basal endometrial thickness, LH on endometrial transition day, E2 on endometrial transition day, P on endometrial transition day, and endometrial thickness on endometrial transition day in live birth group. The multivariate logistic regression analysis showed that the prediction Model 3 for live birth outcome [area under the curve (AUC): 0.917, 95% confidence interval (CI): 0.863 − 0.971, P < 0.001] surpassed the Model 1 (AUC: 0.698, 95% CI: 0.593 − 0.803, P = 0.001), or the Model 2 (AUC: 0.790, 95% CI: 0.699 − 0.880, P < 0.001). The regression equations for the live birth outcomes, integrating tongue and pulse indicators with endocrine parameters, included the following measures: FSH on endometrial transition day [odds ratio (OR): 0.523, P = 0.025], LH on endometrial transition day (OR: 1.277, P = 0.029), TB-L (OR: 2.401, P = 0.001), perPart (OR: 1.018, P = 0.013), h1 (OR: 0.065, P = 0.021), t1 (OR: 4.354, P = 0.024), and h4/h1 (OR: 0.018, P = 0.016). Conclusion In infertility patients undergoing FET, there exists a correlation between tongue and pulse indicators and endocrine parameters. The corporation of tongue and pulse indicators significantly improved the predictive capability of the model for live birth outcomes. Specifically, tongue and pulse indicators such as TB-L, perPart, h1, t1, and h4/h1 exhibited a discernible correlation with the ultimate live birth outcomes.