Statistical analysis
All analyses have been performed using IBM Spss statistics 21.For
continuous variables, Student’s t-test and Mann–Whitney test were used
for data with homogeneous variance and heterogeneous variance
respectively. The x2 test was used for categorical
variables. Logistic regression analyses were conducted to identify
independent correlates between each possible confounding factor,
especially protocols for endometrium preparation and pregnancy outcome
after adjusting for other confounders that were identified in our
univariate analysis. A p-value <0.05 was considered
statistically significant.