When people say they have periods during their pregnancy are referring to implantation bleeding?

Implantation bleeding is not the same as a menstrual period, and it does not occur during pregnancy. Implantation bleeding happens when the fertilized egg implants into the lining of the uterus, usually about 10-14 days after conception. It is typically light and lasts for a few days, and it is not a sign of a period. A menstrual period occurs when the lining of the uterus sheds, which happens when a fertilized egg does not implant or when a pregnancy ends.