Question: is it possible to have implantation bleeding on day 28?
Answer: The fertilized egg then implants into the uterine wall around days 22 to 26 of your cycle. If your body follows a 28-day menstrual cycle, you won't get your period until after day 28. So, if you're bleeding earlier and lighter than normal, there's a good chance it's implantation bleeding, not your period.