A nurse is caring for a client who is 4 hr postpartum and reports they cannot urinate. Which of the following interventions should the nurse implement?

Pouring warm water over the perineal area stimulates the voiding reflex through sensory stimulation and relaxes perineal muscles, which is the most effective non-invasive intervention for postpartum urinary retention. Fundal massage is performed to prevent or treat uterine atony (hemorrhage), not urinary retention. Increasing fluid intake may eventually help but does not address the immediate retention. Cold therapy causes vasoconstriction and would not facilitate urination.