Your post natal bleeding is over after 40th day.
If you saw the flow of the blood, this is your menses. If it is only discharge and spotting, this is nothing.

sheikh,it’s 2 months since I delivered baby.i bathed after 40days and prayed.now I saw little blood it’s not thick it’s thin watery type but brownish red in color.i slept through fajr.its dhuhr now and m confused whether to pray.pls advice ASAP

Menstruation and post-natal bleeding | May 9, 2017 3:37 am
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According to hadith if Brown discharge comes after white water it shouldn’t be regarded as impure but if Brown discharge comes after blood mix with white water will it be regarded as impure or it will be pure.
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My menses cycles usually last for about 7 days, I do ghusul the following night and the next day it’s dry but there may be a bit of brownish discharge I still continue to pray and so on, is that permissible? Is it considered blood or?