The feasibility of a less invasive method to assess endometrial maturation—comparison of simultaneously obtained uterine secretion and tissue biopsy

Objective: to compare the assessment of endometrial maturation parameters in endometrial secretion samples obtained by a novel minimally invasive technique with those assessed in tissue biopsies. Design: prospective study. Setting: university hospital. Population: healthy female volunteers attending a gynaecological outpatient clinic. Methods: endometrial secretion fluid and tissue sampling 5 days after a spontaneous ovulation assessed with ultrasound. Main outcome measures: progesterone (P) receptor, Ki-67 expression and the Noyes criteria were used to date endometrial biopsies. In the endometrial fluid samples, glycodelin A (GdA), leukaemia inhibitory factor (LIF) and P levels were analysed, and protein content and electrophoresis patterns were determined. RESULTS: All data were correlated to estradiol (E2) and P serum concentrations. The dating according to histology and immunohistochemical staining patterns correlated significantly with GdA levels (r=0.376, P=0.048) in endometrial fluid samples as well with serum levels of E2 (r=0.568, P=0.001) and P (r=0.408, P=0.023). No correlation was observed between tissue dating and LIF levels and protein content in endometrial fluid samples. Conclusions: the measurement of GdA in endometrial secretion samples may provide a less invasive method for assessing endometrial maturation in potential conception cycles without disrupting implantation.