Comparative study on the use of mineral oil in the embryological stage of assisted reproductive technology programs

Objective: To investigate the effect of mineral oil type on the development of human embryos during in vitro culture in the context of in vitro fertilization (IVF) programs.

Materials and methods: This study involved zygotes/sibling embryos (1198 embryos) obtained from 84 patients undergoing IVF treatment at the AltraVita Human Reproduction Clinic. After fertilization, the sibling embryos of each patient were cultured for 5–6 days in microdrops of medium, either under a layer of mineral oil or under a layer of paraffin oil. The parameters analyzed included fertilization and embryo cleavage rates, blastocyst formation rates, good-quality blastocyst formation rates, embryo implantation rates, and clinical pregnancy rates.

Results: The group of embryos cultured with paraffin oil showed a significantly higher total number of blastocysts and a higher rate of good-quality blastocyst formation compared to the group of embryos cultured under a layer of mineral oil. Fertilization and embryo cleavage rates, as well as implantation and clinical pregnancy rates, were not statistically significantly different between the two groups.

Conclusion: Coating droplets with medium using paraffin oil during in vitro embryo culture improves the efficiency of the embryological stage compared with the use of mineral oil for the same purpose.