Fertilization, cleavage and blastocyst development according to the maturation timing of oocytes in in vitro maturation cycles.
BACKGROUND
This study was to examine the developmental capacity of oocytes collected from an in vitro maturation (IVM) programme according to their maturation time.


METHODS
The study included 47 IVM cycles that underwent blastocyst transfer. The patients (n = 38) were primed with 10 000 IU HCG 36 h before their oocyte retrieval. The oocytes were classified into three groups: group 1 (n = 139) where oocytes were matured on day of oocyte collection; group 2 (n = 627) where oocytes were matured on day 1 after IVM; group 3 (n = 163) where oocytes matured on day 2 after IVM. Fertilization, cleavage and blastocyst formation were compared between three groups.


RESULTS
Rates of cleavage and blastocyst development in group 3 (72.2%, 96/133; 19.0%, 15/133) were significantly lower than those of group 1 (100%, 108/108; 58.3%, 63/108) and group 2 (91.5%, 487/532; 50.4%, 268/532) respectively (P < 0.01). The number of freezable good quality blastocysts among blastocysts developed from group 1 (52.4%, 33/63) was significantly higher than those from group 2 (35.4%, 95/268) and group 3 (6.7%, 1/15) (P < 0.01). There were 24 clinical pregnancies (51.1%, 24/47) after transfer of the blastocysts and 29 healthy babies were delivered.


CONCLUSIONS
These results suggest that oocytes reaching metaphase II faster in an IVM programme have better embryonic developmental competence.
Son
Weon-Young
WY
Maria Infertility Hospital, Sinseol-dong, Dongdaemun-gu, Seoul 121-742, Korea. weon-young.son@muhc.mcgill.ca
Lee
Seok-Yoon
SY
Lim
Jin-Ho
JH
D000328:Adult; D001755:Blastocyst / Q000166:cytology* / Q000502:physiology; D002454:Cell Differentiation; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D018587:Oocyte Donation / Q000379:methods; D009865:Oocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology
D006063:Chorionic Gonadotropin