Sample size calculation and statistical analysis
We used the following formula for calculating the minimal sample size for this type of study:Previous research estimated that the clinical pregnancy rate of infertile women with thin endometrium after estrogen treatment was approximately 10%, and the clinical pregnancy rate of other similar TCM was approximately 20% (SPSS software 16.0 (SPSS Inc., Chicago, IL) was used to statistically describe and analyze the research results. The quantitative variables were described by mean ± standard deviation (SD) or median ± interquartile range (IQR). The qualitative variables were described by frequency and percentage. Two-sample 