Day 3 is not reliable as day 5 because of the numbers of cells they test. I had several embryos day 3 tested and we let them grow till day 5 and froze them. Day 3 testing revealed that only 3 females were ok.  I demanded testing on the frozen bladtocysts. Those 3 females did develop into the blasts, but when they were retested, only 1 was ok. Other embryos that were found abnormal on day 3 had a normal male bladtocyst.
Personally, i would always choose day 5. Why to put yourself through 12 week testing and God forbid abortion? It would tire you physically and psychologically. It is better to prevent.

 

My clinic only offers NGS PGS at day 5 for reasons of accuracy (e.g. if an embryo is mosaic, can make a better informed decision about transferring or not) and also because it is much less likely to damage the embryo as fewer cells are removed as a proportion of all cells.

I'm so sorry for your loss 

 

My clinic sent me some info on the statistics and finding between a D3 and D5 biopsy. Not much they’ve honestly said. Yes it’s a more in depth test but statistically they are similar on Live Birth rates. And let’s face it that’s the figure we’re all interested in.

So they have suggested a fresh round and D3 testing so I can have a blast D5 transfer if they get that far.

Still not sure on PGS at all but thought that was interesting. It avoids freezing which is where we’ve lost embryos before.