The pivot to IVF without any acknowledgement of the general principles/observations outlined above is entirely unoriginal; it has been discussed in the D&D ad nauseam.
The short answer is that a large egg yield being necessary to render the IVF process viable justifies the inevitable loss of life that drawing such a large yield entails, since life is being unavoidably sacrificed for life. Wanton and/or unnecessary destruction of zygotes or blastocysts (i.e. human persons) is morally reprehensible.