ABSTRACT
Urinary tract infections (UTIs) commonly complicate pregnancy, present in approximately 10% of gestations. Asymptomatic bacteriuria (ASB) is encountered most frequently. Symptomatic infections, cystitis and pyelonephritis, complicate pregnancy less frequently. Female anatomy and the physiologic changes of normal pregnancy impart risk factors for UTIs. Half of women with UTIs during pregnancy have an enlarged bladder capacity, and 15% have a significant post-void residual volume. Normal physiologic changes of pregnancy include a mild hydronephrosis and hydroureter, potentially created by both the mechanical compression of the ureter by the enlarging uterus and pelvic blood vessels at the pelvic brim and the relaxant effect of progesterone on ureteral smooth muscles. An understanding of the changing resistance pattern for E. coli is critical in selecting an appropriate antibiotic, since it is the predominant cause of UTIs.
