Does the lack of caution regarding yellowness (ṣufrah) after ablution for each prayer invalidate the prayer?

The yellowish and brownish discharges (ṣufra and kudrah) are impure (najis). The woman afflicted by them must always prevent the passage of impurity by placing cotton or tying a cloth, as in the hadith (definition) of Hamnah bint Jahsh. A woman experiencing istihada (prolonged non-menstrual bleeding) must take precautions with something that blocks the passage, like cotton. If she does not do so, and the blood reappears, she must repeat her ablution (wudu'). However, if she takes precautions and strives, and the blood still exits, her ablution is valid.