IUI and endo

I have been trying to get pregnant from past one year. Then we were sent to a gynocologist who suggested IUI. The found a cyst like thing on my right ovary which was about 20 mm which they think is endometrosis but they are not sure as they have not diagnosed it. We have finished two IUI and am on third IUI with superovulation tablets. Does any one know if IUI works and would the endometrosis of size 20mm have any side effect Tweet