Normal cycle length is 28-32 days. It can be different in different ladies. Ideal cycle length is 28 days. Delay in periods can be due to many reasons like pregnancy, hormonal imbalance, use of hormonal medicines, polycystic ovarian disease, depression, anxiety, psychological problems, malnutrition, work overload and problems in pituitary gland. First of all you should take pregnancy test if you are sexually active and if the test is negative then visit a doctor for proper diagnosis and treatment.