Pregnancy-related chemotactic activity of human follicular fluid.

We measured chemotactic activity in 238 follicular fluids (FF) aspirated from 45 women who had undergone ovarian stimulation with a combination of clomiphene citrate and human menopausal gonadotropin for oocyte retrieval, in vitro fertilization, and embryo transfer. Fifteen of the treatment cycles resulted in pregnancy. The mean chemotactic activity, measured as the distance in microns granulocytic leukocytes migrated through a 3.0-micron membrane, was significantly higher in FF from conceptual cycles, compared with nonconceptual cycles. Serum chemotactic activity was significantly lower in conceptual cycles, compared with nonconceptual cycles. A chemotactic gradient appears to exist between the peripheral circulation and the ovarian follicle. The gradient favors the follicle in conceptual cycles, as indicated by the chemotactic quotient (the ratio of chemotactic activity of FF to serum). In conceptual cycles the chemotactic quotient was 1.7 +/- 0.17, compared with 0.7 +/- 0.03 for nonconceptual cycles. The presence of leukocyte chemotactic factor in FF appears to discriminate prospectively with a 90% degree of confidence between conceptual and nonconceptual in vitro fertilization and embryo transfer cycles.