Hello, Missed or late periods happen for many reasons other than pregnancy. Common causes can range from hormonal imbalances to serious medical conditions. Other reasons can be 1.     Stress 2.     Low body weight 3.     Obesity 4.     Polycystic ovarian syndrome 5.     Birth control pills 6.      Chronic diseases such as diabetes and celiac disease also can affect your menstrual cycle. 7.Thyroid issues etc. If you have the following symptoms, contact a doctor right away: •     unusually heavy bleeding •     fever •     severe pain •     nausea and vomiting •     bleeding that lasts longer than seven days •     bleeding after you’ve already entered menopause and had no periods for a year Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Enton Dore, General & Family Physician