Publication:

Blastulation rate using fresh versus devitrified oocytes using homologous and heterologous sperm in an assisted reproduction clinic in a middle-income country

Background Assisted reproduction has revolutionized the field of reproductive medicine, giving hope to many couples who face difficulties conceiving naturally. In this case, fresh oocytes and devitrified oocytes play a fundamental role in fertility treatments.

Methods Descriptive, retrospective and observational study in which the records of the HISPAREP reproduction clinic of the Spanish hospital were analyzed in the period from 2020 to 2022.

Results A total of 136 blastocysts that reached day 5 were studied compared to 8 embryos that were blocked before reaching blastulation. Of this, 76 oocytes were fresh, of which 97.4% reached day 5 (74) and the remaining two were blocked. Of the vitrified ones, a total of 68 were devitrified and of these 91.2% reached D5. Of the correctly fertilized oocytes, 96.5% (136) reached blastocysts compared to 5 that were blocked and 3 that were blocked from those that were not fertilized. Regarding the fertilization rate of fresh oocytes, a total of 76 was obtained, which is equivalent to 100%, and of the devitrified oocytes, 65 were fertilized (95.6%) and 3 were not fertilized (4.4%). With a variation of 6.2% in the blastocyst rate, between fresh and devitrified oocytes.

Conclusions There is no significant difference in the reproductive results of fresh and vitrified oocytes. It is necessary to try to carry out more studies with a larger sample size to obtain more conclusive results. The reproductive outcomes of fresh oocytes and oocytes devitrified using fresh sperm and frozen sperm are similar. With this, fresh oocytes have a slightly higher probability of implantation.