Came across this in the intro to ISWTE book - so she had 22 eggs retrieved, of them 19 mature and 19 fertilised (that I believe). But of 19 mature fertilised eggs for 100% of them to make it to blastocyst? Isn't something like 20-30% of eggs in a woman aged 30 (she was late 20s, nearing 30) abnormal? Surely, even with luck and the help of vitamins at least a few would still be abnormal due to natural selection?