First things first: If you have any bleeding at any stage of pregnancy, you should always speak to your healthcare provider right away. But if you've been checked out and all is well, you may have been told your early spotting is due to implantation bleeding, which is a small amount of bleeding (light spotting) that can happen when an egg attaches to the uterus lining.

"Around 1 [in] 4 pregnant women experience spotting or bleeding as one of their early signs of pregnancy," said Yen Hope Tran, D.O., an OB-GYN at MemorialCare Orange Coast Medical Center in Fountain Valley, California. "Implantation bleeding happens around 10 to 14 days after conception, around the same time you may be expecting your monthly period."

So if you don't know you are pregnant, implantation bleeding could be confused with your normal menstrual period.

Why implantation bleeding occurs

"We do not know exactly why implantation bleeding happens," said Kari von Goeben, M.D., a board-certified reproductive endocrinologist and infertility specialist at Kindbody