The most common urinary tract infection in pregnancy is asymptomatic bacteriuria. This condition involves the presence of bacteria in the urine without symptoms and is crucial to detect because it can progress to symptomatic infections like cystitis or pyelonephritis, which carry risks for both mother and fetus. Routine screening and treatment of asymptomatic bacteriuria in pregnancy significantly reduce these complications. Early identification and management are essential to prevent adverse pregnancy outcomes.

Reference: Williams Obstetrics, Cunningham FG, 25th Edition.