A question was posed to Shaikh Ibn ‘Uthaimeen (rahimahullaah):
A woman who has non-menstrual bleeding (istihaadah). Is it permitted for such a woman to perform Duhaa Prayer (the forenoon optional prayer) with the same ablution (wudoo) that she has retained from the Fajr prayer?
This would not be correct. This is because the Duhaa prayer has its own particular time. So it is necessary that she perform wudoo for that in its specified time. That is because this woman is bleeding but not due to menstruation. The Prophet (salallaahu ‘alaihi wassallam) commanded a non-menstrually bleeding woman to perform wudoo for each prayer [in its time]. The time of Dhuhr is from [just past] noon till ‘Asr; and ‘Asr is from the end of the time of Dhuhr till the Sun turns yellow – and the time continues till sunset if there is a necessity. And the time of Maghrib continues till the disappearance of red afterglow (or twilight); and the time of ‘Ishaa is from the disappearance of the red twilight till the middle of the night. And the time of Fajr is from the true dawn until sunrise.
[Majmoo’ Fataawa wa Rasaa’il of Shaikh Ibn ‘Uthaimeen 4/286]