USE OF COCULTURE WITH CUMULUS CELLS IN INSEMINATION MEDIUM IN HUMAN IN-VITRO FERTILIZATION (IVF)

Purpose: In an initial trial, 16 of 33 (48%) bipronuclear human zygotes left in culture in the insemination drop from which they had originated developed to fully expanded blastocysts. Results: This method was subsequently used for all supernumerary embryos judged unsuitable for replacement or cryopreservation on Day 1, 2, or 3 of development. Over a 4-year period, embryos reaching the fully expanded blastocyst stage were cryopreserved. Of 113 such blastocysts thawed, 81 survived (72%), and upon transfer to 52 patients, 8 clinical pregnancies were established (15%), of which 6 were live births. Subsequently, following modification of some culture parameters, 60 patients had 296 supernumerary embryos cultured for 6 days; 43 of these patients (72%) had 148 embryos (50%) that cavitated and 134 (45%) of these cavitating embryos were judged to be fully expanded blastocycts; 125 (42%) of these embryos were cryopreserved. Conclusion: The blastocyst formation rate is similar to that reported by others using conventional culture procedures or coculture on Vero or other cell types. I conclude that cumulus cells are a ready source of feeder cells for the coculture of human embryos.