This chapter reviews conditions occurring in the urinary tract during pregnancy that place the mother, and often the fetus, at risk. Conditions discussed in the chapter that might require surgery during pregnancy include urolithiasis, urinary tract obstruction, accidental and iatrogenic lower urinary tract injury, urethral diverticula, genitourinary fistulas, complications of previous urologic surgery, and urinary tract carcinoma. The normal homeostatic changes involving the urinary tract are frequently responsible for the gravid woman's urinary complaints. The treatment of choice for distal ureteral calculi in pregnant patients who require intervention is cystoscopic examination, followed by either passage of a ureteral stent to relieve obstruction, or ureteroscopy with calculus manipulation. During labor and delivery, the bladder is vulnerable to trauma and injury. Mucosal congestion, submucosal hemorrhage, and capillary oozing around the trigone have been observed cystoscopically after delivery.