The original protocol states that you should skip 1 day of hCG every week when you do a long round (6 weeks-ish) but for a short round (3 weeks-ish) you didn’t have to. The reasoning has been that this prevented immunity to hCG from potentially occurring during a long round.
I used to do the skip injection day to be safe, but actually my final round I had intended on only being a short round and then at the end decided to do another 3 weeks, which means naturally she hadn’t skipped any injections, and nothing bad happened. I haven’t really seen the immunity thing happen myself, so in my mind I don’t really feel like this is something to be too concerned about.
I’m not quite sure just how many skip vs. who don’t, but if you haven’t skipped you can do so just to be sure, but like I said, I’m not sure that it’s really an issue.
I hope that helps!