Vitrification of Human Germinal Vesicle Oocytes: before or after In Vitro Maturation?

Evangelia Kasapi; Byron Asimakopoulos; Katerina Chatzimeletiou; Stamatios Petousis; Yannis Panagiotidis; Nikos Prapas; Nikos Nikolettos

doi:10.22074/ijfs.2017.4717

Vitrification of Human Germinal Vesicle Oocytes: before or after In Vitro Maturation?

Int J Fertil Steril. 2017 Jul-Sep;11(2):85-92. doi: 10.22074/ijfs.2017.4717. Epub 2017 Feb 16.

Authors

Evangelia Kasapi^{1

2}, Byron Asimakopoulos², Katerina Chatzimeletiou³, Stamatios Petousis¹, Yannis Panagiotidis¹, Nikos Prapas¹, Nikos Nikolettos⁴

Affiliations

¹ Iakentro Fertility Centre, IVF Laboratory, Thessaloniki, Greece.
² Democritus University of Thrace, Laboratory of Physiology, Faculty of Medicine, School of Health Sciences, Alexandroupolis, Greece.
³ Aristotle University of Thessaloniki, Medical School, 1st Department of Obstetrics and Gynaecology, Papageorgiou General Hospital, Thessaloniki, Greece.
⁴ Embryokosmogenesis, IVF Laboratory, Alexandroupolis, Greece.

Abstract

Background: The use of immature oocytes derived from stimulated cycles could be of great importance, particularly for urgent fertility preservation cases. The current study aimed to determine whether in vitro maturation (IVM) was more successful before or after vitrification of these oocytes.

Materials and methods: This prospective study was performed in a private in vitro fertilization (IVF) center. We collected 318 germinal vesicle (GV) oocytes from 104 stimulated oocyte donation cycles. Oocytes were divided into two groups according to whether vitrification was applied at the GV stage (group 1) or in vitro matured to the metaphase II (MII) stage and then vitrified (group 2). In the control group (group 3), oocytes were in vitro matured without vitrification. In all three groups, we assessed survival rate after warming, maturation rate, and MII-spindle/chromosome configurations. The chi-square test was used to compare rates between the three groups. Statistical significance was defined at P<0.05 and we used Bonferroni criterion to assess statistical significance regarding the various pairs of groups. The Statistical Package for the Social Sciences version 17.0 was used to perform statistical analysis.

Results: There was no significant difference in the survival rate after vitrification and warming of GV (93.5%) and MII oocytes (90.8%). A significantly higher maturation rate occurred when IVM was performed before vitrification (82.9%) compared to after vitrification (51%). There was no significant difference in the incidence of normal spindle/ chromosome configurations among warmed oocytes matured in vitro before (50.0%) or after (41.2%) vitrification. However, a higher incidence of normal spindle/chromosome configurations existed in the in vitro matured oocytes which were not subjected to vitrification (fresh oocytes, 77.9%).

Conclusion: In stimulated cycles, vitrification of in vitro matured MII oocytes rather than GV oocytes seems to be more efficient. This approach needs to be verified in nonstimulated fertility preservation cases.

Keywords: Fertility Preservation; In Vitro Maturation; Meiotic Spindle; Vitrification.