Does acupuncture increase or decrease IVF sucess the day of transfer? I am torn on what to do.

No change in success. Although very popular in the last 5-6 years, a large multi-center study published in 12/2008 showed that there was no difference in success rates with ivf in couples that did acupuncture vs. Not doing acupuncture. In my experience, that is true, but the one benefit I have seen is that it definitely relaxes you prior to the procedure; and there is no "down" side. Hope this helps.
See research. Here are a series of helpful articles that are very encouraging about acupuncture in conjuncture with ivf: http://yourivfacupuncture.Com/what-is-the-process/research/" rel="nofollow" target="_blank">
May increase success. More research is needed but there are some studies that show increased success when acupuncture is done with ivf. There is no evidence it would decrease success so the worst that might happen is that is won't help. It seems reasonable to try. See http://www.Reuters.Com/article/2012/01/29/us-ivf-acupuncture-idustre80s0pi20120129.