This refers to persistent, actively multiplying bacteria within the urinary tract in asymptomatic women. he incidence during pregnancy is similar to that in nonpregnant women. It var ies from 2 to 7 percent, and it is characteristically population dependent. he highest incidence is in African-American mul tiparas with sickle-cell trait, and the lowest is in aluent white women of low parity. Asymptomatic infection is also more common in diabetics (Schneeberger, 2014).
Bacteriuria is typically present at the first antepartum visit.
An initial positive urine culture result done as a part of prenatal care should prompt treatment. After this, fewer than 1 percent of women develop a urinary tract infection (Whalley, 1967). A clean-voided specimen containing more than 100,000 organ isms/mL is diagnostic. It may be prudent to treat when lower concentrations are identified, because pyelonephritis devel ops in some women despite colony counts of only 20,000 to 50,000 organisms/mL (Lucas, 1993).
Most studies indicate that if asymptomatic bacteriuria is not treated, approximately 25 percent of infected women will develop symptomatic infection during pregnancy (Smaill, 2015). In a more recent study, only 2.4 percent of treated women developed pyelonephritis (Kazemier, 2015). Eradication of bacteriuria with antimicrobial agents prevents most of these serious infections. The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists (2017), as well as the U.S. Preventive Services Task Force (2008), recommend screening for bacteriuria at the first prenatal visit. Standard urine cultures may not be cost efective when the prevalence is low. Less expensive screening tests such as the leukocyte esterase/nitrite dipstick are cost efective when the prevalence is ;2 percent (Rogozinska, 2016; Rouse, 1995). Also, a dipstick culture technique has excellent positive-and negative-predictive values (Mignini, 2009). With this, a special agar-coated dipstick is first placed into urine and then also serves as the culture plate. Because of a high prevalence-5 to 8 percent-at Parkland Hospital, most women are screened by traditional urine culture. Susceptibility determination is not necessary because initial treatment is empirical (Hooton, 2012).
In some but not all studies, covert bacteriuria has been associated with preterm or low-birthweight infants. It is even more controversial whether eradication of bacteriuria decreases these complications. Evaluating a cohort of 25,746 mother-infant pairs, Schieve and coworkers (1994) reported urinary tract infection to be associated with greater risks for low-birthweight infants, preterm delivery, pregnancy-associated hypertension, and anemia. hese findings vary from those of others (Gilstrap, 1981b; Whalley, 1967). Notably, in most studies, cohorts with asymptomatic infection are not evaluated separately from those with acute renal infection (Banhidy, 2007). One Cochrane database review noted insuicient data to answer this question (Smaill, 2015).
Bacteriuria responds to empirical treatment with any of several antimicrobial regimens listed in Table