Document Type

Journal Article

Publisher

Elsevier

Faculty

Faculty of Computing, Health and Science

School

School of Medical Sciences

RAS ID

15011

Comments

Liu, Y., Peirce, K., Yap, K., McKenzie, K., Natalwala, J., Chapple, V., Norman, M., & Matson, P. L. (2012). The fate of frozen human embryos when transferred either on the day ofthawing or after overnight culture. Asian Pacific Journal of Reproduction, 1(3), 187-192. Available here

Abstract

Objective: To study the performance of thawed zygotes and cleavage stage embryos transferred either on the day of thaw or after overnight culture. Methods: A retrospective study of 864 frozen embryo transfer cycles. Cryosurvival rates per thawed embryo and implantation rates were analysed for embryos frozen on Day 1, Day 2 or Day 3 relative to oocyte collection (Day 0) and transferred on the day of thaw or after overnight culture, together with clinical pregnancy rates and prevalence of multiple gestations. Results: Survival of Day 3 embryos was significantly lower than those frozen on Day 1 (P=0.017) or Day 2 (P=0.015). Following overnight culture, resumption of mitosis of zygotes was more frequent than Day 2 (P=0.000) which are in turn higher than Day 3 (P=0.000) embryos. The implantation rate for Day 2 embryos dividing overnight was significantly higher than those that did not divide for women (P=0.001) but not those women (P=0.055). There were no differences in the implantation rates for those dividing or not after culture, for embryos frozen on Day 3 for women (P=0.254) or (P=0.403). Conclusions: Later cleavage stage post-thaw embryos survive and resume mitosis less frequently compared to earlier stages. Embryos not resuming mitosis after culture overnight can implant, particularly Day 3 embryos, suggesting that they can further increase the cumulative pregnancy rate per oocyte collection and that discarding them is wasteful. Overnight culture is best used for logistical reasons rather than a strategy to improve pregnancy rates.

DOI

10.1016/S2305-0500(13)60075-5

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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