A late period here and an early cycle there are common experiences for many women. Stress, travel, a sleepless month, or a sudden change in routine can all affect the menstrual cycle. Because of this, irregular periods are often brushed aside as "just hormones."But doctors say that periods can reveal much more than reproductive health. A cycle that suddenly changes in timing, becomes unusually heavy, turns painfully irregular, or disappears altogether may sometimes be the body's way of raising a red flag.According to Dr Rupinder Sekhon, Principal Lead – Gynae-Oncology & Robotic Surgery, Apollo Athenaa Women's Cancer Centre, "Most women believe that irregular periods are due to shifts in their hormones, and certainly, hormones are a big influence in controlling the menstrual cycle, but irregular periods are not always caused by a change in hormones. If your periods change in their timing, length or flow, at times the body is trying to alert you to a more serious health problem."Here is why paying attention to menstrual changes matters.