I guess that's what happened with us.
My husband and I were about ready to throw in the towel and start considering IUI or saving for adoption or IVF when we decided to continue with testing. It took us 2.5 years to conceive our first, but we lost the baby at 9.5 weeks. When we started trying again, we tried the first month without using OPKs or charting. After that, we tried everything we could possibly think of before consulting with the RE who determined that due to history, there was likely an underlying issue preventing us from conceiving within a normal timeframe.
I don't know if it was the HSG or if we just got lucky that cycle, but if it WAS the HSG, perhaps it was due to clearing a minor blockage in my tubes - or perhaps my hubby's sperm just go into overdrive during the month of March as that is when we conceived both times.

I wish you all the best!