Urinary Tract Infections During Pregnancy

Urinary tract infections (UTIs) are one of the most common medical complications of pregnancy (Mittal & Wing, 2005). It is estimated that one in three women of childbearing age will have a UTI (Duarte et al., 2008). Because of the normal physiologic changes induced by gestation, pregnant women are especially susceptible to these infections. UTIs are characterized by the presence of infectious agents in the genito-urinary tract that cannot be explained by contamination. These agents have the potential to invade the tissues of the urinary tract and adjacent structures. The microbiological profile is well known and pathogens such as Escherichia coli have been present in the vast majority of cases (Sheffield & Cunningham, 2005). The infection may be limited to the growth of bacteria in the urine (which frequently don’t produce symptoms) or it can result in several syndromes associated with an inflammatory response to the bacterial invasion. Actually, the term UTI represent a wide variety of conditions, including asymptomatic forms of UTIs, urethritis, cystitis, acute pyelonephritis and pyelonephritis with bacteremia or sepsis (Joseph DiPiro et al., 2011). There are several classification methods for these infections. In this chapter, we will refer to UTIs as follows:  Asymptomatic bacteriuria is defined as the presence of more than 108 colonies/L of urine, without the symptoms of an acute UTI (Schnarr & Smaill, 2008);  lower tract infection and upper tract infections, according to the anatomical site of contamination (Joseph DiPiro et al., 2011) ;  Lower UTIs: The anatomical site of the infection can be the bladder (cystitis) and/or the urethra (urethritis) (Joseph DiPiro et al., 2011);  Upper UTIs: The kidneys are the anatomical site of the infection (pyelonephritis associated with inflammation of the renal parenchyma, calices and pelvis) (Wagenlehner et al., 2009);  Uncomplicated UTIs: infections occurring in individuals who lack structural or functional abnormalities of the urinary tract that interfere with the normal flow of urine or voiding mechanism (Joseph DiPiro et al., 2011);  Complicated urinary tract infections: infections occurring in individuals with predisposing lesions of the urinary tract that interferes with the normal flow of urine and urinary tract defences. Common causes of predisposing lesions are birth defects,