Can Laxatives Cause A Delay In Periods?

i have been constipated for most of the month of febuary and have been taking laxatives to help relieve me but now I'm 4 weeks late of my period and I was wondering if this could be a side effect of the laxatives. I am also underweight but only by 5 pounds according to my doctor so this should'nt be causing it. what are your thoughts?