Implantation bleeding seems more like spotting than a regular period. According to WebMD, many women do not notice implantation bleeding because it is generally very light and does not last longer than a couple days. For example, certain women may notice a few drops of blood and nothing else.
According to Baby Med, implantation bleeding often looks light pink or brownish in color. Implantation bleeding typically occurs between 6 to 12 days after egg fertilization. Light cramping that resembles menstrual cramping can also occur with implantation bleeding, which is why it is often mistaken for pre-menstrual symptoms and not early pregnancy symptoms.