Histophenotypic Pattern of the Endometrium of the Middle Secretory Phase in Recrudescent Reproductive Failures

Background/Objectives: Normal remodeling of the extracellular matrix of the endometrium is a necessary condition for implantation of a blastocyst. We evaluated whether the use of histochemical «reticulin-collagen» staining can improve the assessment of the extracellular matrix of the middle secretory endometrium in recrudescent clinical/biochemical pregnancy losses in comparison with ultrasound and routine histological examination. Methods: We compared the histochemical pattern of «reticulin-collagen» endometrial biopsy (21st day of the cycle) with ultrasonography and standard histological examination of the endometrium in groups: (1) fertile women with gravity≥2, (gravity=parity) and (2) women with two or more clinical/biochemical pregnancy losses. Results: NP with ordered reticulin fibers forming cellular structures was determined in 92% of biopsies with physiological reproductive status and 44% of biopsies with recrudescent reproductive failures (p<0.05). Despite the fact that there were no differences in ultrasonography and standard histological examination between the groups (p>0.05). Histochemical pattern with disordered abnormal noodle-like reticulin fibers was more common in recrudescent reproductive failures (56%) than in physiological reproductive status (8%) (p<0.001), despite the fact that aNPS was detected only in recrudescent reproductive failures, and in physiological reproductive status was not detected (p<0.00001). Conclusions: We determined the histochemical pattern of the extracellular matrix of the endometrium by the type of «reticulin-collagen», associated in our study with recrudescent clinical/biochemical pregnancy losses, with improved predictability compared to ultrasonography and standard histological examination. We propose to use the method of histochemical evaluation of the «reticulin-collagen» pattern in order to stratify a group of women of fertile age with a risk of reproductive failures.