We are about to do our first frozen embryo transfer (no fresh transfer due to OHSS concerns). Our clinic recommends assisted hatching on all frozen embryos because the freezing process can harden the embryo shells. But from a few hours of internet research, it seems like there is not really any evidence that assisted hatching increases live birth rates for frozen transfers. And it has (minor) risks of damaging the embryo or encouraging it to split into identical twins. So we're not sure it makes sense for a first transfer.
Are we missing something?