LETTER TO THE EDITOR How many eggs should I freeze? TO THE EDITOR: We read with great interest the recent publication by Franasiak et al. (1). They retrospectively report the largest published series to date of blastocysts screened for aneuploidy. It brings to mind a question that often is presented to the infertility specialist with regard to elective oocyte cryopreservation to defer childbearing. How many oocytes should be frozen at a given age to obtain one live birth? Using data from the Franasiak et al. article, additional data from the same subjects, and some arithmetic extrapolation, perhaps we can make an informed estimate of this number as follows:

patients when counseling them in response to a question that we will inevitably hear more and more frequently in the coming years. Edward J. Nejat, M.D., M.B.A. Janelle Luk, M.D. John Zhang, M.D., Ph.D., H.C.L.D. New Hope Fertility Center, New York, New York April 17, 2014 http://dx.doi.org/10.1016/j.fertnstert.2014.05.008

Estimated number of oocytes needed per live birth ðstratified by ageÞ ¼

Mean number of oocytes required to obtain one blastocsyt Percentage of blastocysts biopsied that are euploid  Live birth rate per euploid blastocyst transfer

Of course, the majority of the population studied was presumably infertile, therefore the number of oocytes required per live birth for women seeking elective oocyte cryopreservation who are not infertile would quite possibly be fewer. This approach could assist us in guiding our

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REFERENCE 1.

Franasiak JM, Forman EJ, Hong KH, et al. The nature of aneuploidy with increasing age of the female partner: a review of 15,169 consecutive trophectoderm biopsies evaluated with comprehensive chromosomal screening. Fertil Steril 2014;101:656–63.e1.

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