Author/Authors :
Kasapi، Evangelia نويسنده Iakentro Fertility Centre, IVF Laboratory, Thessaloniki, Greece , , Asimakopoulos، Byron نويسنده Laboratory of Reproductive Physiology - IVF, Faculty of Medicine, Democritus Univ. of Thrace, Dragana, 68100 Alexandroupolis, Greece - Hellas , , Chatzimeletiou، Katerina نويسنده Aristotle University of Thessaloniki, Medical School, 1st Department of Obstetrics and Gynaecology, Papageorgiou General Hospital, Thessaloniki, Greece , , Petousis، Stamatios نويسنده Iakentro Fertility Centre, IVF Laboratory, Thessaloniki, Greece , , Panagiotidis، Yannis نويسنده Iakentro Fertility Centre, IVF Laboratory, Thessal , , Prapas، Nikos نويسنده Iakentro Fertility Centre, IVF Laboratory, Thessaloniki, Greece , , Nikolettos، Nikos نويسنده Laboratory of Reproductive Physiology - IVF, Faculty of Medicine, Democritus Univ. of Thrace, Dragana, 68100 Alexandroupolis, Greece - Hellas ,
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.
