I had the same concern you had over hurting the embryos. First, at the 8 cell stage a cell is the same as any other cell. So you wouldn't be removing a cell that would turn out to be a arm, leg, brain etc. So removing one cell doesn't affect the total number of cells the baby will have or cause other abnormalities.
There was 1 guy in my clinic who usually did the PGD. Since he had the most experience he was the only one who I would let do the PGD. I worked around his schedule since he also worked in a FL office. I am in SC.
PGD is kinda like assisted hatching. They put a tiny slit in the other shell of the embryo and then pull out one cell. They put it on a slide. They do this for all embryos and then ship all of the cells off to be tested.
ALL of my embryos every time survived to day 5 and were not affected by the PGD, They did have fragmentation and unven cells(some small some large) due to the egg quality issue. However, they were not hurt by the PGD. These two issues were fixed on the third cycle by the changes they made.
Because of my genetic condition half of my eggs should be affected and half should not. The first cycle I had 9 that were affected and couldn't be used, 9 there were normal(in terms of only testing for that condition), and 3 that couldn't be determined. The second cycle I ended with 5. I can't remember how many were affected and how many couldn't be determined. And on the third cycle I ended up with 3. They put in all three and 2 of them took. (My boy/girl twins!)
In my case, because it was based on my DNA, they couldn't tell on some of the cells because they were missing DNA, abnormal embryos that wouldn't have worked anyway, or because it just didn't react to the test.
It only cost 2750 each time and that includes the shipping cost. I thought it was very much worth it to ensure my babies would be healthy. Although I don't have any serious issues from my condition, I have a mild form and the babies could have many more sever problems.
We decided against amnio for two reasons. 1.) Once I am pregnant they are my babies and either way I am keeping them. I did everything I could to prevent passing it on and if they have it they have it. There is only a 1-2% chance of error. 2.) Amnio is more risky with twins and after everything we went through to get pregnant I didn't want to take the chance of losing them.
I'm not sure what you are testing for and how your testing will be done. I believe some tests are generic and not based on individual DNA as in my case.
However, the process for the PGD is the same. Normal IVF. Day 3 PGD cell removal, and then day 5 transfer as it takes a day to be tested.
Hope this helps.
IVF # 1 Chem preg Beta #1 49 Beta # 2 33
IVF # 2 Chem preg Beta #1 9 Beta #2 22 Beta #3 168
IVF # 3 BFP
!! 1st beta - 565 2nd 995 3rd 9,269 It's TWINS!!!!