Received July 13, 2019
Accepted December 14, 2019

Objective: Compare laboratory results of embryo development from late matured oocytes in relation of mature oocytes in D+0. Methods: A cross-sectional study was carried out during the period from January to December 2018, in which data collection was done through the medical records analysis. 913 oocytes were collected and divided into 3 groups: group 1 - 643 MII oocytes; group 2 - 119 MI oocytes and; group 3 - 151 PI oocytes. These studied oocytes were from different maternal ages and infertility factors. The analyzed variables were fertilization rate, embryo cleavage, top quality embryos on the third day of development, blastocyst stage, top quality blastocysts, euploid blastocysts, top quality blastocysts and gestation. The data were documented, and the statistical analysis was performed using the chi-square test (p <0.05). Results: All MII oocytes were injected (643), 103/119 MI oocytes and 88/151 PI oocytes that matured late in D + 1, were also injected. The fertilization rate of the 3 groups did not present statistical difference. The oocytes of group 1 presented, statistically, a better prognosis than oocytes of groups 2 and 3 when compared, respectively, embryo cleavage (p = 0.000), top quality embryos on the third day of development (p = 0.000) and blastocyst formation rate (p = 0.004). In the LMO group there were no euploid embryos and, therefore, there was no embryo transfer. Conclusion: Although late matured oocytes have made blastocyst formation possible, even if low rates, there were no viable embryos for transfer.