There is no question that it is a major chesed to help people fulfill a mitzva, and to alleviate people’s suffering. Would you not consider it worthy to help a burn victim obtain plastic surgery!? The only question is as far as priorities are concerned. I assume that in reality that is what you were driving at. This is a major question, as sometimes the enormous amount of money used for one wonderful mitzva could have accomplished 100 different wonderful mitzvos. That you should ask your own halocha advisor.
As an aside, people who need IVF can save an enormous amount by travelling to the country which is the most advanced in the field – Eretz Yisroel.