Cycles are getting longer

We have been trying to conceive since last 3 years. I had a miscarriage when I was in my 20th week. We are trying to get pregnant again. My cycle has always been 32-34 days.  But after the miscarriage I am noticing my cycles have gone longer. Many months it's been 40 days. I have never used ovulation tests. Does anyone have theory's on why suddenly my cycles would get longer. Could this mean I am not ovulating at all?