Have period after you got pregnant: is it possible? No
It is not possible to have your period during pregnancy but it is possible to have bleeding that mimics your period during pregnancy.
Each month your uterus grows a thick lining. This lining is a perfect place for a fertilized egg to implant. If you do not get pregnant that cycle then the thick lining will slough off. The sloughing of this lining is your period. Your monthly period is the lining of the uterus.
If a fertilized egg implants into the lining of the uterus you will be pregnant. The lining creates a perfect place for the egg to grow and the egg will burrow into the lining. This lining feeds the egg and helps the placenta to form and grow.
Since your monthly period is this lining it is impossible to have a period during pregnancy. The lining is necessary for the pregnancy and it is used.
There are many other medical issues that can cause bleeding. The bleeding is often similar to your period and some women even think they are having their period. Some of the bleeding even comes and goes every few weeks, mimicking your monthly period, but it is not your period.
Any bleeding during pregnancy needs to be reported to your doctor right away, especially if it is bright red. There are many causes of bleeding and only your doctor can determine if it is benign or something to be concerned about.