[Endometrial receptivity: numerical classification to successful prognosis in assisted reproduction programs]

BACKGROUND: Currently, the most precise way of predicting uterine receptivity is the histopathological study through endometrial biopsy. Endometrial morphology and thickness are the factors most strongly associated with better pregnancy rates. OBJECTIVE: To evaluate the prediction value of a numerical grade to predict pregnancy in patients exposed to assisted reproductive techniques. PATIENTS AND METHODS: 22 cycles of in vitro fertilization were made at the Instituto para el Estudio de la Concepción Humana in Monterrey, Nuevo León, from June 2003 to January 2004. We evaluated and categorized: endometrial thickness and morphology, vascularity, miometrial ecogenicity, and uterine artery blood flow (including pulsatility and resistance indexes, presence of protodyastolic nicks, and telediastolic flow). The final numerical grade result from the sum of the individual values obtained for each factor. RESULTS: We included 22 cycles of 20 patients. The general pregnancy and implantation rate was of 40 (8/20) and 26% (17/65) per cycle, respectively. The most common diagnosis was tube occlusion (28%), followed by masculine sex (24%), endometriosis (14%), anovulation (14%), and inexplicable (14%). There were no statistical differences among the pregnant and non-pregnant groups regarding: age, hormonal profile (FSH and estradiol, basal and at the tenth day), total of recombinant FSH unities, follicles > or = 14 mm the day of applying human chorionic gonadotropin, aspired eggs, fertilization index, and transferred embryos. CONCLUSIONS: Endometrial maturity is essential for implantation during an assisted reproductive procedure.