Is it permissible to pray with the ablution performed prior to the call to prayer (adhan), if no discharges occurred until the adhan?

If the discharge is continuous and does not stop for a sufficient time for ablution and prayer, then it takes the ruling of سلس ( سلس البول - سلس الريح - سلس الإفرازات - أي ما كان خارجاً من السبيل لا يستطيع المسلم التحكم فيه ويستمر وقتاً طافياً ). If you perform ablution for each prayer, and the time for prayer enters while you are already in a state of ablution, and nothing of this discharge comes out, then your prayer is valid with that ablution, and you are not required to renew it.