Endometrial epithelial cells in peritoneal fluid during the early follicular phase

Peritoneal fluid (PF) was obtained during the early follicular phase in 24 women at laparoscopy as part of infertility investigation. The cells present in PF were pelleted and cultured. Developing endometrial epithelial cell colonies were identified in 19 women (79%). Identification of these cell colonies was facilitated using the monoclonal antibody BW 495/36 as specific marker. The number of endometrial epithelial cell colonies showed a large variation (1 to 200 or more PF sample). No significant distinction in incidence and number of cell colonies was found between women with minimal (n = 11) and without endometriosis (n = 12). A significant correlation with number of cell colonies was found in women with infertility and no mechanical and male infertility factors. These data indicate that retrograde transport of viable endometrial cells during menstruation occurs in most women with patent tubes. Implications of the results for the relation between retrograde menstruation, endometriosis, and infertility are discussed.