Must a mother purify herself and perform ghusl every time her child urinates on her in order to pray?

A woman's cessation from prayer is a grave sin, except during the periods of menstruation or post-natal bleeding (nifas (definition)). Therefore, she must promptly make up for the missed prayers. As for purifying a child's urine, it is obligatory. The Malikis held that what stains the garment or body of a nursing mother is excused if she strives to guard against the impurity of the infant, and it is recommended for her to have a special garment for prayer.