Perinatal and neonatal outcomes of 494 babies delivered from 972 vitrified embryo transfers

Compared with fresh embryo transfers, vitrified day 3 embryo transfer shows no significant differences in obstetrical and neonatal outcomes. Vitrification is a safe method for the cryopreservation of human day 3 embryos.

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Wenhao Shi, M.D., Xia Xue, M.D., Silin Zhang, M.D., Wanqiu Zhao, M.D., Shan Liu, Ph.D., Hanying Zhou, M.D., Min Wang, M.D., Juanzi Shi, Ph.D.

Vol 97, Issue 6 , Pages 1338-1342



To evaluate the safety of vitrification of embryos by comparing the perinatal outcome of vitrified day 3 ETs with fresh cleavage-stage ETs.


Retrospective analysis.


Assisted reproduction center.


A total of 806 women with 494 infants delivered were included.


Supernumerary embryos and embryos of patients at risk of ovarian hyperstimulation syndrome were vitrified using a Cryotop carrier in an open system and were transferred after warming.

Main Outcome Measure(s):

Implantation and pregnancy rates, obstetric outcomes, neonatal outcomes, and congenital birth defects.


A total of 2,543 vitrified embryos were warmed, and 2,375 survived and were transferred. The implantation, pregnancy, miscarriage, and live birth rates were 26.91%, 47.22%, 6.07%, and 38.58%, respectively. In singletons, the mean birth weight was 3,337.44 g, and the mean Apgar scores were 8.91, 9.85, and 9.89 at 1, 5, and 10 minutes, respectively. In multiple gestations, the mean birth weight was 2,556.45 g, and the mean Apgar scores were 8.90, 9.34, and 9.47 at 1, 5, and 10 minutes, respectively. Only seven congenital malformations were observed among the 494 babies. Compared with fresh cleavage-stage ETs, the mean birth weight in the vitrified group was higher in both singleton and multiple gestations. All the other results were similar between the two groups.


Compared with fresh ETs, vitrified day 3 ET shows no significant differences in obstetrical and neonatal outcomes. The study suggests that vitrification with Cryotop is an effective and safe method for the cryopreservation of human cleavage-stage (day 3) embryos.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders. The journal publishes juried original scientific articles in clinical and laboratory research relevant to reproductive endocrinology, urology, andrology, physiology, immunology, genetics, contraception, and menopause. Fertility and Sterility® encourages and supports meaningful basic and clinical research, and facilitates and promotes excellence in professional education, in the field of reproductive medicine.