Acta Scientific Pharmaceutical Sciences

Review Article Volume 1 Issue 5

When to Screen and when to Treat Asymptomatic Bacteriuria in Pregnancy

Shamweel Ahmad 1* and Mohammad Abd-Elqader2

1 Department of Medical Laboratory Sciences, College of Medical Sciences, Prince Sattam Bin AbdulAziz University, Kingdom of Saudi Arabia
2Department of Nursing, College of Medical Sciences, Prince Sattam Bin AbdulAziz University, Kingdom of Saudi Arabia

*Corresponding Author: Shamweel Ahmad, Professor and Consultant Medical Microbiologist, Department of Medical Laboratory Sci- ences, College of Medical Sciences, Prince Sattam Bin Abdulaziz University, Kingdom of Saudi Arabia.

Received: August 05, 2017; Published: October 12, 2017

Citation: Shamweel Ahmad and Mohammad Abd-Elqader. “When to Screen and when to Treat Asymptomatic Bacteriuria in Pregnancy”. Acta Scientific Pharmaceutical Sciences 1.5(2017).


  Although pregnancy is considered as normal event in female's life, complications of it are inevitable. Lot of psychological and physiological changes take place during all trimesters of pregnancy. As these changes are going on; pregnant women become more vulnerable to various kinds of diseases, consequently women and fetus health will be affected. As known prevention is better than cure, also caring is more holistic than curing. Pregnant females are two times more commonly affected than non-pregnant females for the same reasons of urinary stasis and progesterone effect in pregnancy. Urinary tract infection (UTI) during pregnancy could be either symptomatic or asymptomatic. A UTI may manifest as an asymptomatic bacteriuria, acute cystitis or pyelonephritis. Untreated bacteriuria during pregnancy is associated with adverse maternal and perinatal outcomes. Globally asymptomatic bacteriuria affects 2 - 10% of all pregnant women. Many factors such as age, underlying medical conditions, gestational age, level of education, personal hygiene, socioeconomic status, and the commitment to antenatal care are important variables should be illustrated while assessing either symptomatic or asymptomatic bacteriuria in pregnant women. Escherichia coli is the most responsible etiologic agent in both symptomatic and asymptomatic bacteriuria and urine culture is the best golden tool for diagnosis. Untreated bacteriuria during pregnancy is associated with adverse maternal and perinatal outcomes.

  Treatment of either symptomatic or asymptomatic bacteriuria is controversial issue as maternal- fetal health will be affected. The use of antibiotics relies on the outcomes referred to mother and fetus. It is cost effective to screen for bacteriuria if the prevalence rate is 2% or more. It is mandatory to screen all pregnant women for the presence of bacteriuria at their first prenatal visit, prefer - ably in the first trimester and those who are positive should be followed up closely after treatment because as many as one third will experience a recurrence.

Keywords :Antenatal Care; Socioeconomic Status (SES); Pregnancy; Asymptomatic and Symptomatic Bacteriuria


  Asymptomatic bacteriuria is common among women and increases in prevalence with sexual activity, short urethra, pregnancy and easy contamination of the urethra with faecal flora [1]. Asymptomatic bacteriuria is confirmed with positive culture of bacteria containing more than 105 CFU/ml of clean catch, mid-stream urine (MSU) of a patient without symptoms of urinary tract infection (UTI) [2]. Pregnant females are two times more commonly affected than non-pregnant females for the same reasons of urinary stasis and progesterone effect in pregnancy [3]. On the other hand despite of the causative agent, some studies showed there is no difference in incidence of bacteriuria between pregnant and non-pregnant females. However, the incidence of acute polynephritis among pregnant women with bacteriuria is increased which makes pregnancy as risk factor and pregnant ladies as risk group [4].

  Various workers examining the prevalence of bacteriuria among pregnant women have reported varying percentage prevalence rates of bacteriuria. It has been observed that the prevalence of bacteriuria among non-pregnant women was from 8 - 10% and the percentage prevalence rate among pregnant women could be as high as 15% [5]. Registration of pregnant women to antenatal clinic early in 1st trimester is necessary to detect and treat underlying asymptomatic bacteriuria to avoid complications later in pregnancy. High prevalence of bacteriuria observed in the first trimester could be as a result of underling asymptomatic urinary infection before pregnancy ensued or at unset of pregnancy due to changes associated with it. Asymptomatic bacteriuria in pregnancy may cause complications such as pylonephritis, hypertensive disease of pregnancy, anaemia, chronic renal failure, premature delivery and foetal mortality [6,7].

Anatomical and pathophysiological considerations associated with UTIs in females and during pregnancy

  Usually the anatomical description of the female urinary tract represented by wide and short urethra and proximity from the anus makes females more suspected to have UTIs in their life which could be considered as first suspected scenario explaining the disease process. However, as pregnancy is going on through the third trimester, the enlarged uterus makes prolonged pressure over the urinary bladder which result in decreased motility and increased urine stasis over time, eventually might increase the chances of bacterial growth which could be the second scenario of the pathophysiological consequence for susceptibility more related to pregnancy. As early as the eighth week of pregnancy the renal pelvis and ureters begin to dilate and the bladder itself is displaced superiorly and anteriorly [8] . The principle cause of hy - droureter and hydronephrosis is the mechanical compression from the enlarging uterus but smooth muscle relaxation induced by pro- gesterone may also play a role. Smooth muscle relaxation results in decreased peristalsis of the ureters, increased bladder capacity and urinary stasis. Bacterial growth may be facilitated by differences in urine pH and osmolality and pregnancy-induced glycosuria and aminoaciduria [9].

  Through middle of the second trimester all physiological chang- es of pregnancy that affect the urinary tract already happened, thus at the week eighteen of gestational age is the preferred time for conducting the routine urine culture as the best diagnostic test for bacteriuria [10] . To detect bacteriuria different examinations are used which include complete urinalysis, leukocyte esterase activity, a nitrite test, and urine cultures. Still a midstream urine culture is considered the best diagnostic test [11] . Screening for ASB in preg- nant women has been shown to be cost effective when compared with treating UTI and pyelonephritis without screening [12] .


  Antenatal care (also known as perinatal care) refers to the reg- ular medical and nursing care recommended for women during pregnancy. "Prenatal Care" [13] . Urinary tract infections (UTI) af- fects all age groups, but women particularly pregnant women are more susceptible than men, due to short urethra, pregnancy, easy contamination of urinary tract with fecal flora and various other reasons [14] . Asymptomatic bacteriuria is defined as the presence of significant bacteriuria without the symptoms of an acute urinary tract infection and it seems to be associated more with pregnancy. Symptomatic urinary tract infections are divided into lower tract (acute cystitis) or upper tract (acute pyelonephritis) infections [15] and in terms of measurements asymptomatic bacteriuria is defined as bacterial growth of greater than or equal to 105 colony form - ing units per milliliter urine of the same organism, using midstream urine collection specimens, in the disappearance of symptoms of UTI [16-18].

  The prevalence of bacteriuria in pregnancy is closely correlated to socioeconomic status (SES) [4] . Different studies have shown that characteristic problems related to infection control in devel- oping countries include bad antibiotic prescribing practices, poorly functioning laboratory services, lack of surveillance data and sub- optimal design or construction of buildings and water and sanita - tion systems. Overcrowding of facilities and insufficient numbers of health workers are commonly noted. Increased bed numbers, nurse to patient ratios and bed space are known to have negative effects on infection transmission. Managers roles are not well specified, which contributes to the poor quality of services [19-21] .

  Wherever poverty found always combines with sickness and lack of awareness about basic principles of infection control and disease eradication worldwide and specifically in developing world. The prevalence of significant bacteriuria determined by a single catheterized urine at delivery was 2% in pregnant women of middle socioeconomic status (SES) compared to 6·5% in preg- nant females of low socioeconomic status (SES) [22] . Another study showed that 60% of the affected women belonging to low SES while 40% belonging to middle class [23] . There is no signifi - cant relation to the level of education between the infected and uninfected patients [24] . A difference clearly identified in the prevalence of asymptomatic bacteriuria between the urban and rural citizens of the same nationality when they found prevalence of asymptomatic bacteriuria among Bangladeshi pregnant ladies living in London was 2.0% and 12% in rural areas in Bangladesh. Cleanness is vital in promoting pregnant women health, in the op- posite malpractice and bad personal hygiene certainly contributes to disease development as well the complications [25,26] .

  Both Asymptomatic and symptomatic bacteriuria require proper medical interventions as prolong the maternal-fetal health will be affected, however shifting from asymptomatic to symptom- atic bacteriuria may happen dramatically in approximate of 10% of those with asymptomatic bacteriuria develop symptomatic bacteriuria during pregnancy [27] . Proper use of the antibiotic is essential in minimizing the complications; a study conducted by Verma., et al. 2016 [28] considered nitrofurantoin as the selected antibiotic against commonest pathogens causing the disease. In addition to the safety properties in pregnancy as well its bioavail - ability in urine makes it the drug of choice.

  Shifting to symptomatic bacteriuria will result in serious up- per urinary tract infection (pyelonephritis) which could lead to obstetrical and gynaecological complications as preterm delivery (prematurity), [29] which is also supported by the "Canadian's Communication Group Screening" when they titled bacteriuria as associated with 50% increase in the risk of premature delivery.

  Low birth weight is another complication reported by Thomas., et al. 2011, [30] increase fetal mortality rate, [23] pre-elampsia, [31] hypertension and anemia, [32] and post-partum endometri - tis [33] . So, time is crucial in diagnosis and treatment, therefore if asymptomatic bacteriuria is left untreated in pregnancy, it will result in up to 40% of pregnant women to develop UTI and about 25 - 35% of patients to develop acute pyelonephritis [34] .

  The right diagnosis will lead to right treatment, and early de - tection and appropriate treatment is the main concern as it will limit the infection rate to 3% [35] . The effect of age on the prob- ability of being attacked seems to be pronounced, disproportional relation describes the relationship between age and incidence of asymptomatic bacteriuria among pregnant ladies. A study showed that 55% of the affected ladies between the age group 26 - 30 years with the highest percentage, and 20% of the infected ladies of the age 35 years [24] .

  General health and underlying medical condition is a vital deter - minant and good predictor for the prognosis of both symptomatic and asymptomatic bacteriuria. Medical condition like diabetes mel- litus and pregnancy increase the risk of pyelonephritis and renal impairment [36-38].

  Many studies have observed that most cases of asymptomatic bacteriuria occur during 3 rd trimester (40%) of pregnancy [1] . Posi - tive proportional relation can best describe the relationship be- tween the gestational age and the incidence of disease occurrence, as the growing fetus makes prolonged pressure over the urinary bladder, this will result in frequent urination (urgency feeling and may incontinence) but without complete emptying of the bladder, urine stasis occurs over time and alters urine PH through decreas- ing level of acidity finally results in bacterial growth.

  The dominant organism causing bacteriuria during pregnancy is the Escherichia coli , a study conducted by Ahmed., et al. 2011 [39] showed that the sensitivity pattern of all isolated organisms reflects that all were sensitive to ciprofloxacin and gentamicin. While it was found in another study that Pipercillin Tazobactum, amikacin and nitrofurantion to be the most effective antibiotics against the uri- nary isolates [1] . The upsurge in antibiotic resistant pattern could be due to antibiotic abuse and self-medication. Also, low cost and availability of drugs could be another contributing factor for anti - biotic resistance [1] .

  Proper antibiotic treatment of ASB is effective in reducing the incidence of pyelonephritis and low birth weight, but there was no evidence of a reduction in preterm delivery [40] .

  Following the standards of personal hygiene during pregnancy and even in normal circumstances is an integral part of the preven- tion process.

  It is important to explain all females about the proper way of cleaning the perianal-urogenital area, and risk of acquisition of UTI. The cleansing process to be started from the cleanest area to less clean area, which means the process goes from the front to back to avoid undesired irreversible transmission of organisms to the urinary tract. Prenatal (antenatal) visits are not less important, it is designed to promote the maternal wellbeing as well to limit the complications during pregnancy. The antenatal visits foster the ways of communication between the pregnant ladies and the health care providers through filling gaps and finding channels that encourage therapeutic communication to enforce health educa- tion; health promotion; disease prevention and social support [41]. The importance of the prenatal care comes from conducting urine screening in the first prenatal visit and during the third trimester of pregnancy as secondary prevention to limit diseases and prevent further complications as it recommended by the American college of obstetrics and gynecology (ACOG) [42] .

  Restricted resources, easy accessibility to health facilities, and underlying general medical condition such as malnutrition, ane- mia, and even the pregnancy as it suppresses the immune system can induce risks [43] .

  Many limitations are present in health care system in dealing with infection control measures in developing world, misuse of antibiotics prescription, poorly functioning laboratory depart- ments; and shortage of qualified nursing staff will lead to imbal - ance in nurses- patients ratio, and all involve in transmission of infection [19] .

  Change is an ongoing process always needed in parallel as the need for actions in the understanding and implementation of in- fection control measures [44] .

  Cost-effectiveness of the infection control measures should be considered in mind when making simple comparison between the various costs and outcomes of two or more different inter - ventions. The cost of extended hospitalization due to infection is thought to exceed those of improving infection control measures. In the USA, reduction of infections by only 6% would offset the cost of an infection control programmer by savings from reduced hospitalization [44] . A study in India showed that care for lon- ger stay, hospital acquired bacteraemia in a cardiac hospital cost US$15,000 more per patient, when compared to patients who did not develop infection [45] . In Mozambique, single dose prophylac - tic antibiotics at emergency Caesarean section was found to cost less than a tenth of a post-operative, seven-day regimen, with no significant difference in infection rates [46] .

  Patient education is a part of the treatment required at all stag- es of disease process, and it always expected from the health care provider to enhance the patient to be an active agent and decision maker over the demands of her condition including active partici- pation in the treatment plan.

Clinical recommendations
  1. It is mandatory to screen all pregnant women for the pres - ence of bacteriuria at their first prenatal visit, preferably in the first trimester and those who are positive should be followed up closely after treatment because as many as one third will experience a recurrence [29] .
  2. Pregnant women who have asymptomatic bacteriuria should be treated with antimicrobial therapy for three to seven days [47,48] .
  3. Patients with two or more episodes of bacteriuria are fol- lowed up with monthly repeat cultures until delivery to en- sure urine sterility during the pregnancy [49] .


  Health promotion and screening as secondary prevention mea- sure through an early detection and treatment is highly recom - mended to maintain maternal wellbeing, doing urine culture on regular basis during the pregnancy as indicated in antenatal care visits are integral part of the prevention process as well limiting obestrical and gynecological complications during pregnancy. The 18th week of the gestation age is the optimal time for screening of bacteriuria. It is recommended to screen pregnant mothers early in their pregnancy and treat those with significant bacteriuria as this could significantly minimize adverse maternal and foetal outcomes.

  Proper self-care and personal hygiene is the prevention key measure. Furthermore, focusing on the enhancement commitment to antenatal care visits, increase level of awareness and health edu- cation of pregnant women will help in prevention of complications to a great extent.


  1. Girishbuabu RJ., et al. “Asymptomatic bacteriuria in pregnancy”. International Journal of Biological and Medical Research 2.3 (2011): 740-742.
  2. Jepsen OB., et al. “Urinary tract infection and bacteriuria in hospitalized medical patients”. Journal of Hospital Infection3.3 (1982): 241-251.
  3. Cunningham FG., et al. “Renal and urinary tract disorders, Williams Obstetrics. (24th edition), McGraw-Hill Medical Publishing Division, New York (2014).
  4. Whalley P. “Bacteriuria of pregnancy”. American Journal of Obstetrics and Gynecology 97.5 (1967): 723-738.
  5. Kass EH. “Bacteria and diagnosis of infections of the urinary tract”. Archives of Internal Medicine 100 (2002): 709-712.
  6. Foxman B. “Epidemiology of urinary tract infections, morbidity and economic cost”. American Journal of Medicine 113(1A) (2002): 5S-13S
  7. Musbau S and Muhammad Y. “Prevalence of bacteriuria among pregnant women attending clinic at Federal Medical Centr Ng- uru Yobe State”. Scholars Journal of Applied Medical Sciences 1.5 (2013): 658-660.
  8. Fried AM. “Hydronephrosis of pregnancy: ultrasonographic study and classification of asymptomatic women”. American Journal of Obstetrics and Gynecology 135.8 (1979): 1066-1070.
  9. Jeyabalan A and Lain KY. “Anatomic and functional changes of the upper urinary tract during pregnancy”. Urologic Clinics of North America 34.1 (2007): 1-6.
  10. Stenqvist K., et al. “Bacteriuria in pregnancy. Frequency and risk of acquisition”. American Journal of Epidemiology 129 (1989): 372-379.
  11. Tolosa JE. “Antibiotics for Asymptomatic Bacteriuria in Pregnancy: RHL commentary (last revised: 14 January 2008)”. The WHO Reproductive Health Library; Geneva: World Health Organization.
  12. Jones LA., et al. “Urinary tract infections in pregnancy”. eMedicine (2009).
  13. “Prenatal Care”. US National Library of Medicine. (2012).
  14. Enayat K., et al. “Asymptomatic bacteriuria among pregnant women referred to outpatient clinics in Sanandaj, Iran”. International Brazilian Journal Of Urology 34.6 (2008): 699- 707.
  15. Connolly A and Thorp JM. “Urinary tract infections in pregnancy”. Urologic Clinics of North America 26.4 (1999): 779-787.
  16. Merritt AD and Sanford JP. “Sterile-voided urine culture: an evaluation in 100 consecutive hospitalized women”. Journal of Laboratory and Clinical Medicine 52 (1958): 463-470.
  17. Kass EH. “The role of asymptomatic bacteriuria in the pathogenesis of pyelonephritis”. In: Quinn EL, Kass EH, eds. Biology of pyelonephritis. Boston: Little, Brown (1960): 399-412.
  18. Norden CW and Kass EH. “Bacteriuria of pregnancy—a critical appraisal”. Annual Review of Medicine 19 (1968): 431-470.
  19. Raza MW., et al. “Developing countries have their own characteristic problems with infection control”. Journal of Hospital Infection 57.4 (2004): 294-299.
  20. Hambraeus A. “Lowbury Lecture: Infection control from a global perspective”. Journal of Hospital Infection 64.3 (2005): 217-223.
  21. Shears P. “Poverty and infection in the developing world: Health care related infections and infection control in the tropics”. Journal of Hospital Infection 67.3 (2007): 217-224.
  22. Turck M., et al. “Bacteriuria of pregnancy. Relation to socioeconomic factors”. The New England Journal of Medicine 266 (1962): 857-860.
  23. Fatima N and Ishrat S. “Frequency and risk factors of asymptomatic bacteriuria during pregnancy”. Journal of the College of Physicians and Surgeons Pakistan 16.4 (2006): 273-275.
  24. Robina Ali., et al. “Asymptomatic Bacteriuria among Pregnant Women”. A.P.M.C 5.2 (2011).
  25. Ullah MA., et al. “Prevalence of asymptomatic bacteriuria and its consequences in pregnancy in a rural community of Bangladesh”. Bangladesh Medical Research Council Bulletin 33.2 (2007): 60-64.
  26. Versi E., et al. “Bacteriuria in pregnancy: a comparison of Bangladeshi and Caucasian women”. International Urogynecology Journal - and Pelvic Floor Dysfunction 8.1 (1997): 8-12.
  27. Bailey RR. “Urinary tract infection”. Canadian Dental Association 107 (1972): 315-330.
  28. Verma A., et al. “Asymptomatic bacteriuria and antibacterial susceptibility during pregnancy”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology 5.2 (2016): 407-410.
  29. Macejko AM and Schaeffer AJ. “Asymptomatic bacteriuria and symptomatic urinary tract infections during pregnancy”. Urologic Clinics of North America 34.1 (2007): 35-42.
  30. Thomas MH., et al. “Urinary tract infections and asymptomatic bacteriuria in pregnancy (online)”. (2011).
  31. Savage WE., et al. “Demographic and Prognostic characteristics of Bacteriuria in Pregnancy”. Medicine 46.5 (1967): 385-407.
  32. Robertson JG., et al. “The Management and Complications of Asymptomatic Bacteriuria during Pregnancy. Report of study of 8, 275 Patients”. Journal of obstetrics and gynaecology of the British Commonwealth 75 (1968): 59-65.
  33. Romero R., et al. “Meta-analysis of the relationship between Asymptomatic Bacteriuria and Preterm Delivery New Birth Weight. Obstetrics Gynerecol 73.4 (1989): 576-82.
  34. Guberman C., et al. “Urinary tract, Gastrointestinal and Dermatologic Disorders in pregnancy”. In: Current diagnosis and treatment; obsterics and gynaecology, 10th edition (edited by Decherny AH, Nathan L, Goodwin TM, Laufer N) 23 (2007): 374-385.
  35. Smaill F. “Antibiotics for asymptomatic bacteriuria in pregnancy”. The Cochrane Database of Systematic Reviews 2 (2001): CD000490.
  36. Nicolle LE. “Asymptomatic bacteriuria—important or not?”. The New England Journal of Medicine 343.14 (2000): 1037-1039.
  37. Harding GK., et al. “Antimicrobial treatment in diabetic women with asymptomatic bacteriuria”. The New England Journal of Medicine 347 (2002): 1576-1583.
  38. Makuyana D., et al. “Asymptomatic bacteriuria among outpatients with diabetes mellitus in an urban black population”. The central African journal of medicine 48 (2002): 78-82.
  39. Shamweel A, Shakooh S, Salati SA, Muniem A. “Prevalence of asymptomatic bacteriuria among Pregnant women in Kashmir”. Sri Lanka Journal of Obstetrics and Gynaecology 33.4 (2011): 158-162.
  40. Smaill F and Vazquez JC. “Antibiotics for asymptomatic bacteriuria in pregnancy”. The Cochrane Database of Systematic Reviews 2 (2007): CD000490.
  41. Sugathan KS., et al. “Promoting institutional deliveries in rural India: The role of antenatal-care services”. National Family Health Survey 45-Subject Reports no. 20, International Institute for Population Sciences and East-West Centre.
  42. “ACOG. Antimicrobial therapy for obstetric patients. ACOG Educational Bulletin, Washington, DC: American College of Obstetricians and Gynecologists”. 245 (1998): 8-10.
  43. Pittet D., et al. “’Clean care is safer care’: the global patient safety challenge 2005-2006”. International Journal of Infectious Diseases 10.6 (2006): 419-424.
  44. Haley RW., et al. “The efficacy of infection surveillance and control programs in preventing nosocomial infections in US hospitals”. American Journal of Epidemiology 121.2 (1985): 182-205.
  45. Kothari A., et al. “Costs associated with hospital-acquired bacteraemia in an Indian hospital: a case-control study”. Journal of Hospital Infection 71.2 (2009): 143-148.
  46. Kayihura V., et al. “Choice of antibiotics for infection prophylaxis in emergency cesarean sections in low-income countries: cost-benefit study in Mozambique”. Acta Obstetricia et Gynecologica Scandinavica 82.7 (2003): 636-641.
  47. Nicolle LE., et al. “Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults”. Clinical Infectious Diseases 40.5 (2005): 643-654.
  48. Nicolle LE. “Asymptomatic bacteriuria: when to screen and when to treat”. Infectious Disease Clinics of North America 17.2 (2003): 367-394.
  49. Chen KT. “UTI in pregnancy: 6 questions to guide therapy”. OBG Management 16.11 (2004): 36-54.

Copyright: © 2017 Shamweel Ahmad and Mohammad Abd-Elqader. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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