Does a late period effect ovulation?


Well, I tend to have a pretty regular cycle, especially when I work out (which I know is fairly normal). Sometimes my cycle is off and my period is late due to stress or weight gain or whatever it may be. Does this mean that my ovulation would be off too? If my period changes to different times two months in a row, how would this effect my ability to get pregnant?

I've never really gotten into cycle length and how all of that works until recently, so I have a lot of questions that I am trying to figure out. Thank you in advance everyone :)