Letrozole

So for three cycles my dr had me take two 2.5 letrozole then a week or so later they'll have me trigger with 200mg ovidrel... they just upped my letrozole today to 3 pills now will this help my chances with getting pregnant? We've been trying for three and half years with one miscarriage 2 years ago. We've tried to rounds of letrozole and trigger shot with timed intercourse but didn't work so we did one cycle of IUI and that also failed and will be trying IUI again just hope them upping the letrozole will have a positive out come! Advise or experience will help me please.