A prospective randomized study to compare four different mineral oils used to culture human embryos in IVF/ICSI treatments.

OBJECTIVE(S): We aimed to evaluate and compare the embryo quality at early cleavage stages using different oils overlaying media to culture human embryos during IVF/ICSI treatments.

STUDY DESIGN

A total of 500 IVF/ICSI treatments from 500 women were analyzed in a prospective randomized study. Oocytes/embryos were treated into microdroplets of appropriate media overlaid with (i) Mineral Oil (CryoBioSystem, L'Aigle, France) (group 1, n=129), (ii) Liquid Paraffin (Medicult, Lyon, France) (group 2, n=126), (iii) Nidoil (Nidacon International, Guthenburg, Sweden) (group 3, n=126) and (iv) Ovoil (Vitrolife, Kungsbacka, Sweden) (group 4, n=119). Comparisons between groups were done using two by two post hoc tests, with 5% significance. The primary endpoint was the embryo quality, defined as good or top quality when embryos were with (i) less than 20% of fragmentation and (ii) 3-5/4 cells at day 2 or 6-10/8 cells at day 3, respectively.

RESULTS

At day 2, the embryo quality was similar in all groups. However, the mean number of top quality embryos at day 3 was statistically higher into the group 4 (1.4+/-1.8) compared to the group 1 (0.9+/-1.0; p=0.03) and 2 (0.8+/-1.3; p=0.05). Furthermore, a significant increase of the mean number of good quality embryos was observed at day 3 into the group 4 (2.6+/-2.6) compared to the group 1 (1.6+/-1.6; p=0.02).

CONCLUSION(S): The embryo quality could be modified according to commercial oils used to overlay culture media.