What Can Cause Delayed Periods?

I am a thirty two years old women.My first delivery was on 10th may 2010.But the baby was died one day before delivery date.After the delivery i have regular periods upto september 2010,now periods are regular.But Last month i had the mensturation cycle after thirty days.This month it was delayed by five days.Whether there is any problem in my health.What is the reason for the delayed mensturation.What are the measures to be taken for pregnancy?