Urinary Tract Infection in Pregnancy

Introduction

Urinary tract infections (UTIs) are second in frequency only to respiratory tract infections in the general practice of medicine^[1]. Females are more prone than males to UTIs, and this tendency seems to increase during pregnancy. This increased predisposition to UTIs during pregnancy is partly the result of the pressure of the gravid uterus on the ureters causing stasis of urine flow and is also attributed to the hormonal and immunological changes that occur during normal pregnancy^[1].

We report on a study carried out at King Abdulaziz University Hospital, Jeddah, that was designed to determine the frequency of significant bacteriuria in healthy pregnant females and its impact on pregnancy.

MATERIAL AND METHODS

In a prospective study conducted over a one-year period from 1987 to 1988, midstream urine samples were collected from 2642 pregnant females who had no apparent underlying medical ailments. All patients were attending the antenatal clinic at King Abdulaziz University Hospital, Jeddah. The urine samples were collected under supervision, using proper aseptic precautions, and were cultured using the Dip Strip technique^[2]. Colonies were identified using standard methods^[3]. Gram-negative bacilli were identified using the AP120E system.

Subjects who were found to have significant bacteriuria (i.e., those with a bacterial count over 100,000 organisms per milliliter in a fresh “clean catch” urine specimen^[4]) were divided into two groups: those with asymptomatic bacteriuria, and those with symptoms of UTI (i.e., cystitis and/or pyelonephritis). All patients were monitored, as were 200 pregnant subjects with a negative urine culture, matched by age, gravidity, and gestational age.

The frequency of occurrence of diabetes, hypertension, anemia, and premature birth were recorded for each group in accordance with standard criteria^[5–7].

Final data were collected and statistically analyzed using the chi-square test.

RESULTS

Of 2642 midstream urine specimens collected from pregnant females, 419 (15.8%) exhibited significant bacterial growth. One hundred eighty-eight (7.1%) subjects were asymptomatic and 231 (8.7%) had symptoms suggestive of UTIs.

Gram-negative micro-organisms were isolated in 89% of the specimens, and Escherichia coli was the most common, followed by Klebsiella.

Table 1 compares the age and gravidity of the symptomatic and asymptomatic groups with those in the control group. No statistically significant difference was found among these groups.

Table 1. Mean ± standard deviation of age and gravidity in the three groups.

Development of hypertension and anemia during pregnancy was found to be more common in patients with significant bacteriuria in both the symptomatic and asymptomatic groups, compared with the control group (P < 0.05). The frequency of prematurity was statistically significant in symptomatic patients only, as compared with the control and asymptomatic groups (P < 0.05); however, no statistically significant difference was found between the control and asymptomatic groups. Tables 2 and 3 outline the occurrence of premature birth, diabetes, hypertension, and anemia in the control, asymptomatic, and symptomatic groups.

Table 2. Frequency of complications in symptomatic bacteriuric pregnant patients.

Table 3. Frequency of complications in asymptomatic bacteriuric pregnant patients.

DISCUSSION

Information regarding UTIs and their influence on pregnancy still remains incomplete for the Saudi population. Different reports published from various centers in the Kingdom have focused on the overall prevalence of UTIs. A preliminary report from Riyadh Military Hospital reported a 7.2% incidence of bacteriuria among 1886 urinary specimens obtained from male and female patients^[8]. A second report from King Fahd Hospital of the University in Al-Khobar and King Faisal University in Dammam described the presence of significant bacteriuria in 17.4% of 530 inpatients and 5.7% of 1016 outpatients^[9]. A third report from King Abdulaziz University Hospital, Jeddah, cited a 12.2% overall prevalence of UTI, and infection was more frequent in females than in males, with a ratio of 2:1^[10].

In our present study, we found 15.8% of the pregnant women had significant bacteriuria; 7.1% of them were asymptomatic and 8.7% were symptomatic. The 7.1% incidence of significant asymptomatic bacteriuria is comparable to that reported in the medical literature, with figures that vary from 2 to 10%, depending on the method used for testing and the socioeconomic status of the patients^[11].

Despite earlier studies that showed the incidence of premature birth is higher in patients with bacteriuria^[11], we found this to be true only for the symptomatic group. Patients in the asymptomatic bacteriuric group did not exhibit any significant difference from the control group in this regard.

Although diabetes is a multifactorial disease, its etiological relationship with significant bacteriuria during pregnancy remains unclear^[11]. The fact that diabetes developed during pregnancy in a significant number of patients with bacteriuria, as compared with the control group in our study, is rather interesting. Whether this represents a possible result or a cause in this group of patients remains debatable.

Preeclampsia has been reported to occur more frequently when bacteriuria is present, although this finding has not been demonstrated universally^[12].

Our study showed that hypertension and anemia in pregnancy are more common in women with bacteriuria, regardless of whether they have symptoms of UTI.

Our study did not consider the effect of treatment on the outcome of pregnancy and the various medical conditions associated with significant bacteriuria, but highlights the fact that the presence of significant bacteriuria during pregnancy puts the patient in a high-risk category, regardless of whether the patient is symptomatic or not.