All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
If a woman becomes pure after post partum bleeding but before the end of forty days and then has blood discharges within this period, then this blood is considered as post partum bleeding, and she should not pray or fast during this bleeding, but if she becomes pure again, she has to perform Ghusl (ritual bath) and then should fast and perform the prayer. This is the view of 'Ataa' and Ash-Sha'bi as it is bleeding within the period of post partum bleeding [40 days], so it is considered as post partum bleeding like the first one, and her husband should not have sexual intercourse with her; this is also one of the two narrations from Ahmad.
Allaah Knows best.