It is not possible to have a true menstrual period while pregnant. However, light vaginal bleeding can happen during pregnancy, especially in the early stages.
This type of bleeding is common in some women and may happen around the time a period would normally be expected. Because of the timing, it can sometimes be mistaken for a menstrual period.
This bleeding is known as implantation bleeding and occurs when the embryo implants in the lining of the uterus. Although it can look similar to a period, implantation bleeding is usually lighter, shorter, and may appear pink, light red, or brown.
If you are pregnant and experience any vaginal bleeding, see an OB-GYN for an evaluation. Although bleeding during pregnancy is less common, it can also be a sign of miscarriage or other pregnancy-related problems.