Iui w/ 3 mature follicles at time of trigger shot, 90mil sperm count at 85% motility. what are our chances?

Depends: Pregnancy rates depend on many factors (ie low amh or fsh is high) then chances will be lower. Additionally, are both tubes open or only one? Preganancy rates should be individualized and should be a % provided by the physician providing your care. I would call the office performing the procedure and ask them but typically IUI alone its 2% per cycle, Clomid (clomiphene) with IUI 10% and hmg with IUI is 15 %.

IUI helps Clomid (clomiphene): Good response to stimulation. If your baseline pr is 5%/month without treatment (i.e. Infertile), this probably moves it up to 15%-20% (the normal fertility rate). If it fails, some people will take fsh drugs (gonadotropins). Be sure your day#3 fsh, esradiol, and amh levels are good (i.e. Ovarian reserve tests). This is important due to age. Ivf is an option with icsi, too, if this fails.