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.
We have already clarified in Fatwa 82539 that the discharge which comes out of the bladder is impure, so it is an obligation to cleanse after this discharge and wash the clothes that are touched by it as it is not permissible to perform ablution before cleansing [from this discharge]. Al-Buhooti from the Hanbali school said: 'It is an obligation to cleanse after relieving oneself, either after urinating or defecating, with the exception of passing wind, and it is not valid to perform ablution or Tayammum (dry ablution) after urinating or defecating and before cleansing.'
As regards performing ablution before the beginning of the time of the prayer, and performing supererogatory prayers with the same ablution, and whether the ablution is nullified when wearing clothes and so forth, the answer is as follows:
If the discharges are continuous, then its ruling is the same as that which applies to bleeding outside the monthly periods and to the one who has incontinence of urine. In such a case, you should perform ablution for every prayer after its time is due according to the majority of the scholars. The evidence is that Abu Daawood reported that the Prophet said regarding a woman who has bleeding outside her monthly menses: "She should perform ablution for every prayer (i.e. when its time is due)." Ibn Qudaamah said: 'This is because it is a purification due to a necessity, and thus it is bound with the due time (i.e. of prayer). If the one to whom this necessity applies (having an incontinence of urine or irregular discharges) performs ablution before the time of the prayer starts, and then has some discharges (or urine…etc.) coming out, then his ablution will be void.'
However, if she performs ablution after the time of the prayer starts, then she may perform supererogatory prayers as much as she wishes, either before or after the obligatory prayer until the time of the following prayer starts. It is valid and sufficient for her to recite and touch the Quran with the same ablution which she performed for the obligatory prayer, this applies also to Tawaaf (circumambulation around the Ka'bah) [she may do so with the same ablution]. Nevertheless, her ablution is not invalidated by wearing clothes or waiting for the Imaam if her discharges continue to come out after she had performed ablution after the time of the prayer had begun unless her ablution is invalidated by another thing than these discharges, like urinating or defecating, in which case she is obliged to renew her ablution.
Allaah Knows best.