Dear friend, thank you for your question which I am more than pleased to answer. Let me give you an overview of our results and some comments: IAKENTRO, FERTILITY CENTRE Frozen embryo Clinical pregnancy rates 2011 < 35 yrs (62,1%), 35 - 37 yrs (47,4%), 38 - 40 yrs (41,4%), > 40 yrs (32,1%) Clinical pregnancy rates are the same between frozen and fresh embryos. There are some publications indicating that there might be an advantage transferring frozen to fresh embryos in a new cycle. There is only same concern regarding survival of the blastocyst during the procedure of freezing and thawing, that is because 5-10% of the total blastocysts (5th day embryos) undertaking this procedure will not survive. Those embryos though that will survive hold the same or even better chances of giving a clinical pregnancy and a live birth. You can find more information if you guide through our site into the section of results. Let me just add that IAKENTRO performs over 2000 IVF/ICSI cycles per year and sustains a well established donation progarm. We are at your disposal for any further information.