Wa `alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Chronic vaginal discharge requires only performing wudu (ablution) for the obligatory Prayer after its time has begun as well as wearing sanitary pads. However, washing is not required for each Prayer. Also, after performing the obligatory Prayers, you may perform any optional prayers or read the Qur’an.
In this regard, the late prominent Saudi scholar, Sheikh Ibn`Uthaymeen, who said,
After offering the obligatory Prayers, she may offer any optional prayers or read the Qur’an. In fact, she can do any of the permissible things, as specified by scholars, just like the person who suffers from urinary incontinence.
However, if the discharge comes and goes, and it usually stops during the time of Prayer, then she should delay her Prayer until the times when it stops, so long as there is no fear that the time of the Prayer will end.
If she fears that the time for the Prayer will end, she should perform wudu and wear a sanitary pad and pray. It makes no difference whether there is a slight or a heavy discharge, because all of it is coming from the same place and even a little of it invalidates wudu.
Allah Almighty knows best.
Source: Excerpted with modifications from www.islamqa.info