1 Anywhere from 5 - 15 days after the egg is fertilized, some women notice bleeding spotting which they confuse with a period. 2  In normal cases the bleeding is much lighter than a period and only last 2-4 days. 3  So all in all, if someone tells you that you can be pregnant, and have your period, they're wrong. A period is to drain your menstrual blood, lining and eggs, which in pregnancy are needed to protect the fertilized egg or eggs. 2  So there for you CAN NOT be pregnant and have your period. 3  I'll explain why some women THINK they are on their period.