ANSWER:

What you do unknowingly, you are not accountable for it, however, if you deliberately swallow blood, the fast is invalid and you must make it up.

Shaikh i have a long term problem of gum bleeding sometimes i might swallow it unintentionally not knowing my saliva might contain blood does that effect my fast while sleeping also my gums do bleed and what about sputum that goes inside directly in to throat from nose when a person lie dowm to sleep i am always stressed and thinking whether my fast is accepted or not ?