Frequently I am asked about IUI compared to IVF and specifically about NC IVF compared with IUI. Although IUI can be successful, there are clear limitations to an IUI. First of all, unless pregnancy occurs an IUI does little to explain why a couple has failed to conceive.
Could the tube have failed to catch an egg(s)? Could the sperm have failed to find an egg(s)? Could the sperm have failed to fertilize an egg(s)? Could the fertilized egg(s) have failed to grow? Could the embryo(s) have failed to make it to the uterus and failed to implant?
The answer to all of these questions following a failed IUI is "we don't know."
This is the reason that IVF is a powerful diagnostic as well as therapeutic tool. It is so difficult to counsel a patient undergoing a stimulated IUI cycle with multiple dominant follicles. On the one hand you have to say "well, there are 6 good follicles so we could end up with 0-6 babies..." Then when it fails (which is more often than it succeeds) you have to say "well, we really have no idea why it didn't work." Very frustrating indeed.
The FASTT Trial aimed to look at the impact of omitting FSH/IUI for patients with unexplained infertility who were <40 years old. Its results clearly demonstrated the superiority of IVF first compared with FSH/IUI then IVF if FSH/IUI were unsuccessful. I think that NC IVF is also superior to IUI. Perhaps the comparable option would be CC/IUI but I think that NC IVF is likely superior to even FSH/IUI in cases where a couple has no previous pregnancies or there is possible male factor or possible tubal factor or endometriosis. Since many patients do not have a laparoscopy these days, it could be that many of them have an element of tubal disease or endometriosis and clearly IVF would be superior in these patients.
So for those wanting to conceive FAST.....think about the results of the FASTT trial and give strong consideration to IVF. It is not the only option but it may be the best option...whether it is NC IVF or stimulated cycle IVF.
A randomized clinical trial to evaluate optimal treatment for unexplained infertility: the fast track and standard treatment (FASTT) trial. Fertil Steril. 2010 Aug;94(3):888-99. Reindollar et al.