Can you have a period and still be pregnant?!?

Hello ladies, Im very curious to hear your thoughts, knowledge and experiences.

Everything I’ve read says its medically impossible to have an actual period and still be pregnant. Yet I have met women who say they have in fact had a period then found out they were pregnant. My own mother being one of them. She claims she had a period with both my siblings. So Im curious to hear if any of you have experienced this? And if so, was it a normal period or just spotting? And did you have cramps and other period related symptoms like bloating ect.??

Thanks and Blessed Day to all❤️