1. Is the zona pellucida thickness of human embryos influenced by women's age and hormonal levels? 
Hanna Balakier, Ph.D., Agata Sojecki, M.Sc., Gelareh Motamedi, M.Sc., Siamak Bashar, M.Sc., Rodica Mandel, M.Sc., Clifford Librach, M.D. 
Fertility and Sterility 
Volume 98, Issue 1, Pages (July 2012)
DOI: /j.fertnstert
Copyright © 2012 American Society for Reproductive Medicine Terms and Conditions

2. Figure 1
Day 3, 8-cell, grade 1 embryo from 39-year-old patient (×600). Measurements of zona pellucida thickness (ZPT) were taken at five different sites (in micrometers). The mean ZPT is μm and the SD is 3.74 μm, which reflects considerable ZPT variation.
Fertility and Sterility  , 77-83DOI: ( /j.fertnstert )
Copyright © 2012 American Society for Reproductive Medicine Terms and Conditions