The many anatomical and physiological changes occurring during pregnancy affect the entire urinary tract. These changes can induce various urological diseases, alter renalfunction and can be life-threatening to the foetus and the mother Some changes can persist post partum. Asymptomatic bacteriuria must be investigated and treated to prevent about 40% of pyelonephritis and a twofold higher premature delivery rate. Duplex ultrasound is the reference examination to diagnose renal colic due to stones and a low-dose IVU can be proposed whenever there is a doubt about the diagnosis. Treatment is conservative. Lower urinary tract symptoms are very frequent and some disorders, such as stress incontinence, can persist after delivery. This review article describes the anatomical and physiological changes observed during pregnancy and their pathological consequences on the urinary tract in order to detect, prevent and treat these disorders.