Barrenetxea G, Romero I, Celis R, et al. - Researchers aimed at determining the predictive value of different parameters to assess endometrial receptivity among assisted reproduction treatments, which involve conduction of single embryo transfer of frozen-thawed euploid blastocysts. They conducted an observational study recruiting 104 patients at a University associated assisted reproduction center. A multivariable logistic (binomial) analysis was performed after hormonal preparation to evaluate the correlation of different parameters (age, body mass index (BMI), duration of hormonal preparation, plasmatic progesterone levels, endometrial parameters at ultrasound assessment and endometrial receptivity determined by endometrial receptivity assay (ERA)). In the univariate analysis, a correlation was observed between BMI, doses of progesterone administered before biopsy and the receptivity of endometrium. No relationship between age of women, duration of hormonal supplementation, and the results of ERA test was observed. In these series, there was no relationship of endometrial receptivity to either endometrial thickness or plasmatic progesterone levels. In the multivariate analysis, they identified the predictive value of both, BMI and cumulative progesterone administered prior to the test, for endometrial receptivity.