There is no specific time that it is safe to leave a urinary tract infection untreated, as any delay in treatment can lead to serious complications, according to the Mayo Clinic. Infected individuals should visit a doctor as soon as possible after symptoms appear to quickly stop the infection before it spreads to the kidneys and causes further, possibly irreversible, damage.
According to the Mayo Clinic, an untreated urinary tract infection can cause permanent kidney damage and make a woman more susceptible to recurrent urinary tract infections. In pregnant women, a urinary tract infection can cause premature delivery. Antibiotics are used to treat urinary tract infections; typically, symptoms alleviate within one to three days after the start of treatment. However, it is important for patients to complete the entire course of medication to ensure that the infection is completely gone.
According to the U.S. Department of Women's Health and Human Services, urinary tract infections are caused by bacteria entering the urinary tract. This can occur as a result of wiping from back to front after a bowel movement, having sexual intercourse, waiting too long to pass urine or using a diaphragm. People experiencing signs of a urinary tract infection, such as pain during urination, foul-smelling urine and pressure in the lower belly, should see a doctor for a full evaluation.