Human oocyte maturity in vivo determines the outcome of blastocyst development in vitro.
OBJECTIVE
To date, the impact of oocyte maturity at aspiration on the blastocyst formation in vitro has not been fully evaluated. This study was undertaken to assess the influence of oocyte maturity in patients undergoing in vitro fertilization and blastocyst transfer program.


METHODS
A total of 1278 oocytes derived from 147-IVF cycles were retrospectivly analyzed. Oocyte maturity was graded on a scale from 1 to 5 based on the morphology of the ooplasm, cumulus mass, corona radiata, and membrana granulosa cells.


RESULTS
Mature oocytes yielded the highest fertilization rates. Although the cleavage rates were similar in both groups, the percentage of poor morphology, day-3 embryos from the nonmature-oocyte group was significantly higher than from the mature-oocyte group (54.7% vs. 15.5%, P < 0.001). Although good morphology, day-3 embryos were collected from nonmature oocytes, the incidence of these embryos developing to the blastocyst stage was significantly less than from mature oocytes (33.3% vs. 71.2%, P < 0.001). Although blastocyst stage embryos were collected from nonmature oocytes, the incidence of these embryos developing to the top-scoring blastocysts was significantly less than from mature oocytes (58.3% vs. 89.5%, P < 0.001).


CONCLUSIONS
These phenomena suggest that oocyte maturity produced in vivo determine the fertilization potential and subsequent blastocyst quality in vitro.
Lin
Yi-Chi
YC
Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
Chang
Shiuh-Young
SY
Lan
Kuo-Chung
KC
Huang
Hsuan-Wei
HW
Chang
Chih-Yang
CY
Tsai
Meng-Yin
MY
Kung
Fu-Tsai
FT
Huang
Fu-Jen
FJ
D001755:Blastocyst / Q000502:physiology*; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D066298:In Vitro Techniques; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy