Is assisted hatching performed on all embryos?
In some cases yes. We have good data showing that in some groups (e.g. women over 38 years of age, previous failed IVF cycles, unusually thick zonae pellucida) assisted hatching will increase the implantation and pregnancy rates. There has only been one study carried out looking at the impact of performing assisted hatching on every single embryo of all couples and the conclusion was that it did not increase the expected pregnancy rates. Is summary, assisted hatching is certainly helpful in some cases but is probably not necessary in all cases.
