Received November 17, 2013
Accepted November 17, 2013

OBJECTIVE: To compare the preimplantation embryo development to culture embryos continuously or renewal of fresh medium on day 3, using a unique medium in oocyte donation cycles. METHODS: It was compared the development of 364 embryos in 48 cycles of oocyte donation that were grown without interruption until day 5/6 versus 621 embryos in 82 cycles of oocyte donation cultured until day 5/6, with renewal of fresh medium on day 3. In both cases were used Global media from IVFonline. The period studied was from September 2012 to February 2013. We compared the following rates: good quality embryos on day 3 (6-10 cells, <10% fragmentation, without multinucleation), blastocyst formation, and good quality blastocyst (trophoblast and innrer cell mass with grade A or B). RESULTS: No significant differences were observed for the parameters analyzed. CONCLUSIONS: Preimplantation embryo culture until the fifth or sixth day in the single medium, can be performed without interruption or with renewal at day 3, not affecting embryonic development.