The Alpha consensus meeting on cryopreservation key performance indicators and benchmarks: proceedings of an expert meeting  Alpha Scientists in Reproductive Medicine  Reproductive BioMedicine Online  Volume 25, Issue 2, Pages 146-167 (August 2012) DOI: 10.1016/j.rbmo.2012.05.006 Copyright © 2012 Reproductive Healthcare Ltd. Terms and Conditions

Figure 1 Cryopreservation key performance indicators (KPIs): range of respondents’ estimates for each question. Box-and-whiskers plots of the respondents’ estimates for each question of the KPI survey (see text for the specific questions asked regarding each developmental stage). The box represents the values from the lower to upper quartile, with the middle line representing the median. The limits of the bars show the minimum and maximum values excluding outlying values (smaller than the lower quartile minus 1.5×IQR and larger than the upper quartile plus 1.5×IQR). Outlying values are presented individually. Reproductive BioMedicine Online 2012 25, 146-167DOI: (10.1016/j.rbmo.2012.05.006) Copyright © 2012 Reproductive Healthcare Ltd. Terms and Conditions

Figure 2 Pathways for the movement of water and cryoprotective additives (CPAs) across the plasma membrane. The movement of water becomes more efficient with embryo development to the blastocyst stage, as the Arrhenius activation energy declines. (A) Movement of CPAs and water through the plasma membrane is via simple diffusion in the early developmental stages (A1) and via channel diffusion (aquaporins) by the blastocyst stage (A2). (B) Movement of water and CPAs by simple diffusion or via channels also depends on the type of CPA. (C) The efficiency of dehydration and CPA uptake is also influenced by cell size, increasing with increasing surface/volume ratio (cell size highlighted). Reproductive BioMedicine Online 2012 25, 146-167DOI: (10.1016/j.rbmo.2012.05.006) Copyright © 2012 Reproductive Healthcare Ltd. Terms and Conditions

Figure 3 Metaphase-II human oocyte features during vitrification/warming. (A–E) Vitrification: (A) MII oocyte before equilibration; (B) oocyte shrinking at equilibration; (C) oocyte recovery at equilibration; (D) full-size recovery at equilibration; (E) shrunken oocyte in vitrification solution before loading on the carrier device. (F–I) Warming: (F) oocyte at first step of warming (1M sucrose solution) on release from the carrier device; (G–H) oocyte shrinking during the second step of warming (0.5M sucrose solution); (I) oocyte recovery during final washing. Reproductive BioMedicine Online 2012 25, 146-167DOI: (10.1016/j.rbmo.2012.05.006) Copyright © 2012 Reproductive Healthcare Ltd. Terms and Conditions