This is just my experience, I started pregnacare gummies just after my period Jan 8th,my periods have been regular for 10 years 28/29 days. My period did not come on time so took test, it was a BFN. A couple of people have mentioned that vitamins lengthening cycles and after a week late i made the decision to stop taking vitamins. I stopped taking them just over two weeks ago and today, CD48 my period started. I'm putting this thread up as information. Obviously I cant completely say 100% that it was the vitamins, as I am nearly 44 and it could be perimenipause, as the cause. I wonder how many others have had delayed periods due to vitamins?