After the postpartum lochia clears up in 40 days, if menstruation occurs 10 days later, what is the reason?

Patient's question:

Sure, here is the translation of the provided content into English:
No

Doctor's answer:

Hello, under normal circumstances, lochia usually clears up around 42 days after childbirth, which is normal. Moreover, some women may have their period as early as the full moon. However, in your case, it could be possible that there are residual tissues in the uterus. It could also be due to inflammation, or the uterus may not be contracting properly. Additionally, a follow-up check-up should be done around 42 days. You should go to the hospital for an examination now.