Purity: Continuous Bleeding for a Woman Without a Habit

Practical Laws of Islam as per the teachings of Ayatullah Sistani

Ruling 509:

If a woman who does not have a habit of duration for ḥayḍ experiences bleeding for one or more months after giving birth, the bleeding on the first ten days is nifās and the bleeding on the second ten days is istiḥāḍah. As for the bleeding after that, it is possible that it could be ḥayḍ or istiḥāḍah; to determine whether it is ḥayḍ or not, she must act according to the instructions mentioned in the previous ruling.

-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)