There are many causes of menorrhagia, including polycystic ovary syndrome, endocrine disorders, pregnancy, mental stress, overwork, anemia, etc. All of these may lead to menorrhagia. If you find that your period is late, you should have a chorionic gonadotropin test to see if you are pregnant. After you rule out pregnancy, you should have an ultrasound of the uterus to see how the endometrium is developing and a sex hormone test to see if there are abnormal hormone levels and polycystic ovary syndrome. If the period is only delayed for a week, it is considered normal. A regular period is 28 days, and a week early or late is considered normal.