Survival rate of human oocytes and pregnancy outcome after vitrification using slush nitrogen in assisted reproductive technologies.
OBJECTIVE
To report the survival rate of oocytes and the rate of successful pregnancies obtained from super-rapid cooling of oocytes using slush nitrogen (SN(2)).


METHODS
Prospective clinical research.


METHODS
A university-affiliated hospital.


METHODS
Twenty-eight infertile women who underwent 30 cycles of IVF-ET using previously vitrified oocytes.


METHODS
Oocytes were vitrified by super-rapid cooling using SN(2).


METHODS
Morphological normality of thawed oocytes and clinical outcome.


RESULTS
In 30 cycles of ovarian stimulation for IVF, 364 surplus oocytes from 28 patients were vitrified using SN(2). Three hundred two (85.1% +/- 2.9%) of the oocytes survived after warming. Fertilization and cleavage rates were 77.4% +/- 3.5% (168/218) and 94.3% +/- 2.1% (158/168), respectively. Thirteen pregnancies (43.3%) resulted from 30 uterine transfers of 120 embryos with an implantation rate of 14.2% (17/120). There were no differences between the pregnancy rate after vitrification/warming and that obtained from routine noncryopreserved oocytes.


CONCLUSIONS
The present report suggests that super-rapid cooling may improve the clinical efficacy of human oocyte vitrification and may be a valuable tool for human assisted reproductive technologies.
Yoon
Tae Ki
TK
Fertility Center of CHA General Hospital, CHA Research Institute, Pochon CHA University, College of Medicine, Seoul, Korea. tkyoon@cha.ac.kr
Lee
Dong Ryul
DR
Cha
Soo Kyung
SK
Chung
Hyung Min
HM
Lee
Woo Sik
WS
Cha
Kwang Yul
KY
D000328:Adult; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D009584:Nitrogen; D009865:Oocytes; D011247:Pregnancy; D011256:Pregnancy Outcome; D027724:Reproductive Techniques, Assisted
D009584:Nitrogen