A simplified coculture system using homologous, attached cumulus tissue results in improved human embryo morphology and pregnancy rates during in vitro fertilization

Purpose: This study was undertaken to evaluate simplified methods of human embryo coculture using either attached or nonattached autologous cumulus ti ssue. Methods: Eight hundred one zygotes were cultured for 48 hr in a prospective , randomized trial comparing culture of embryos either with intact cumulus tissue, with cumulus tissue added to the droplet of culture medium, or with out any cumulus tissue. In a follow-up study, embryo quality, pregnancy rat es, and implantation rates were compared in 120 consecutive patients underg oing in vitro fertilization with a coculture system using cumulus tissue co mpared to a cohort of 127 patients undergoing IVF immediately preceding the institution of the coculture protocol. Results Embryo morphology was significantly improved (P < 0.05) following c ulture with attached cumulus tissue (5.61 +/- 0.29) and culture with added cumulus tissue (4.72 +/- 0.31) compared to that of embryos grown in culture medium without cumulus tissue (3.95 +/- 0.26). The clinical pregnancy rate improved from 39.4% (50/127) to 49.2% (59/120) following institution of a system of coculture with attached cumulus tissue. Conclusions: These data indicate that a simple coculture system using autol ogous cumulus tissue can result in improved embryo morphology, implantation rates, and clinical pregnancy rates during in vitro fertilization, This co culture system is simple, is non-labor intensive, and eliminates many of th e risks which may be present in other embryo coculture systems.