Can a hsg test unblock a fallopian tube?

Not exactly : An hsg won't unblock a truly blocked fallopian tube. That being said it does clean it out by removing excess mucus. Interestingly, there is a higher rate of pregnancy after women have an hsg test done.

Depends, but...: It depends on the reason the tube is blocked. Simple 'plugging' or 'clogging' with mucus might be opened by hsg, altho these plugs might clear on their own. An hsg cannot clear blockage due to inflammation, such as infection. To my knowledge, all studies since the late 1980s fail to show an increased pregnancy rate after hsg.