How many days before a period does implantation bleeding occur?

Implantation bleeding usually occurs about 6-12 days before your expected period date.

In simple terms, about implantation bleeding:

1. When pregnancy occurs, the egg attaches to the cavity of the uterus.
2. This process can cause light bleeding in the uterine lining, which is called implantation bleeding.
3. It is usually light-colored blood or spotting, lasting only a few hours to 1-2 days.
4. It is not heavy bleeding like a period, and there is usually little pain as well.
5. So if light bleeding occurs right before your expected period, it could be implantation bleeding.