To expand on what notimetorelax said, egg harvesting is a low risk but not a zero risk procedure which involves preparatory hormone injections, twilight sedation, and ultimately sticking a pretty fat needle into the ovaries. There's roughly a 1 in 1000 chance of serious complications for any woman that goes through it. If you're over 40 and your last round of harvesting only produced a handful of eggs cells and all of them with some kind of defect, repairing a damaged egg or zygote would be much less risky for the mother. What exactly the cost of a treatment based upon this discovery would be, I have no idea, but both processes are resource intensive.