How safe is germinal vesicle stage oocyte rescue? Aneuploidy analysis of in vitro matured oocytes.
OBJECTIVE
To evaluate the rate and type of aneuploidies of chromosomes 13, 16, 18, 21 and 22, with respect to the length of in vitro maturation (IVM) period, and to compare the results to previously published studies on aneuploidy rates of unfertilized, uninseminated mature oocytes and first polar bodies.


METHODS
Two hundred and twelve immature germinal vesicle stage oocytes were assigned to two groups. After successful IVM, depending on their maturational period of 24h (Group A) or 36h (Group B), chromosomal analysis was performed by five color fluorescence in situ hybridization (FISH). In Groups A and B the rates of aneuploid oocytes were calculated and compared by chi-square test. Also the rates of hyperhaploidy, hypohaploidy, disomy and nullisomy were determined and compared by chi-square test. The difference was considered statistically significant at p-value of <0.05.


RESULTS
The prolonged IVM did not significantly affect the aneuploidy rate compared to the shorter maturation period (48.1% and 45.0%, respectively). Regarding the unbalanced premature chromatid separation, no statistically significant difference was found between hyperhaploidy and hypohaploidy (14.8% versus 8.3%). For chromosome nondisjunction, higher frequency of disomy than nullisomy was observed (30.6% versus 14.8%; p<0.05). The estimated global aneuploidy rate was between 42% and 63%.


CONCLUSIONS
The aneuploidy rate of IVM GV-oocytes is comparable to the aneuploidy rate of in vivo matured oocytes and first polar bodies, regardless of the length of maturation period. This suggests that the immature oocytes can be used in infertility treatment after they complete maturation.
Vlaisavljević
Veljko
V
Department of Reproductive Medicine and Gynecologic Endocrinology, Maribor Teaching Hospital, Ljubljanska 5, SI-2000 Maribor, Slovenia.
Krizancić Bombek
Lidija
L
Vokac
Nadja Kokalj
NK
Kovacic
Borut
B
Cizek-Sajko
Mojca
M
D000328:Adult; D000782:Aneuploidy; D002877:Chromosomes, Human / Q000235:genetics*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007247:Infertility, Female / Q000628:therapy; D054315:Oocyte Retrieval / Q000379:methods; D009865:Oocytes / Q000254:growth & development*; D010062:Ovulation Induction / Q000379:methods