If you have been trying to get pregnant for a year (if you're under 35) or six months (if you're over 35), and you have not been successful, it's time to move on to the specialist. Once there, what are your choices?
If you are otherwise healthy--the doctor will do every blood test known to man to determine that--then the question is "are your tubes clear?" To determine this, you'll have to have an HSG, or hydrosalpingogram. This involves injecting dye into the uterus and then using X-ray to see if the dye spills out into the abdomen. If it does, the tubes are clear. IUI is then an option.
If the tubes are not clear, then the question is "why?" Do you have an infection in your tubes? Is it something that can be removed or treated? If not, then not only is IUI not an option, but IVF may not be successful either. The reason is that an infection in the tubes can leak fluid back into the uterus, irritating the lining, and making implantation of an embryo unsuccessful.
Let's say the tubes are clear. You now can consider IUI or IVF. You may be wondering why I said both are options before you've even tried IUI. The reason is that each unsuccessful IUI costs you something...in terms of money and time. Every month you try IUI is another month you get older. The odds of success with IVF in any given month are higher than IUI, no matter what your age. And with IVF, if you're young and produce a good number of eggs, you could have leftover embryos to use later.
Financially speaking, if you add up the cost of several IUIs versus IVF, there comes a point where the costs are the same, and if you're still not pregnant, then you still have to go on to IVF. Of course, there is no guarantee that you'll get pregnant on your first IVF cycle either.
You have to assess the situation for yourself in terms of finances, time and emotional cost. Every unsuccessful month is really emotionally hard! If you decide to try IUIs, then give it your best shot--add in the injectables to increase the number of follicles you grow each month, and put a limit on how many cycles you'll try before moving on to IVF. And pick the best possible doctor in your area or else travel to a better doctor.