eMedicine Specialties > Emergency Medicine > Obstetrics & Gynecology

Pregnancy, Urinary Tract Infections

Author: Allison M Loynd, DO, Resident Physician, Department of Emergency Medicine, Wayne State University School of Medicine, Detroit Receiving Hospital
Coauthor(s): Adam J Rosh, MD, Assistant Professor, Department of Emergency Medicine, Wayne State University/Detroit Receiving Hospital
Contributor Information and Disclosures

Updated: Aug 5, 2009

Introduction

Background

Urinary tract infections (UTIs) are one of the most common bacterial infections during pregnancy. UTIs are associated with risks to both the fetus and the mother, including pyelonephritis, preterm birth, low birth weight, and increased perinatal mortality. The prevalence rates of bacteriuria in pregnant women and nonpregnant women are essentially the same.1 UTIs are more common in women when compared with men, primarily because of the anatomic differences of the shorter urethra and its proximity to the vagina and the rectum. However, when pregnant women have a urinary tract infection, they have a higher risk for and increased occurrence of upper tract UTIs when compared with lower tract UTIs.

Several physiologic changes occur during pregnancy that cause otherwise healthy women to be more susceptible to serious sequelae from urinary tract infections.2 The infections can be symptomatic or asymptomatic. Asymptomatic bacteriuria, as the name implies, is a positive urine culture without specific symptoms. Asymptomatic bacteriuria increases the risk for an upper tract UTI, also known as pyelonephritis. Treatment of asymptomatic bacteriuria reduces the risk of a symptomatic infection.3

Pathophysiology

Remarkable changes occur in the structure and function of the urinary tract during pregnancy. Blood-volume expansion is accompanied by increases in the glomerular filtration rate (GFR) and urinary output. The ureters undergo tonic relaxation because of the mass production of hormones, particularly progesterone. This loss in tone, along with the increased urinary tract volume, results in urinary stasis, which, in turn, can lead to dilatation of the ureters and the calyceal pelves. Urinary stasis and the presence of vesicoureteral reflux predispose some women to upper tract UTIs and acute pyelonephritis.

Frequency

United States

The frequency of asymptomatic bacteriuria occurs in 2-7% of pregnancies, similar to the nonpregnant population. However, up to 40% of these may progress to symptomatic upper tract UTI or pyelonephritis, significantly more than in nonpregnant women.4 Several factors are associated with an increased frequency in various patient populations. Indigent patients have a 5-fold increased incidence of bacteriuria compared with that of nonindigent patients. The risk is doubled in women with sickle cell trait. Other risk factors for bacteriuria include diabetes mellitus, neurogenic bladder retention, and a history of previous urinary tract infections.

Mortality/Morbidity

Untreated upper tract UTIs are associated with low birth weight, prematurity, premature labor, hypertension, preeclampsia, maternal anemia, and amnionitis.5 A retrospective population-based study by Mazor-Dray et al showed that urinary tract infection during pregnancy is independently associated with intrauterine growth restriction, preeclampsia, preterm delivery, and cesarean delivery.6

Race

When socioeconomic status is controlled, no significance difference among the races seems to exist.

Sex

Urinary tract infections (UTIs) are 14 times more frequent in women than in men. This difference is attributed to several factors: (1) the urethra is shorter in women; (2) in women, the lower third of the urethra is continually contaminated with pathogens from the vagina and the rectum; (3) women tend not to empty their bladders as completely as men; and (4) exposure of the urogenital system to bacteria during intercourse.

Clinical

History

The presentation varies depending on whether the patient has asymptomatic bacteriuria, a lower tract UTI (cystitis), or an upper tract UTI (pyelonephritis).

  • Pregnant women with asymptomatic bacteriuria usually are diagnosed incidentally on routine urinalysis and urine culture.
  • Burning with urination (dysuria) is the most significant symptom in pregnant women with symptomatic cystitis.
  • The usual complaints of increased frequency, nocturia, and suprapubic pressure are not particularly helpful, because most pregnant women experience these as a result of increased pressure from the growing uterus.
  • Symptoms of pyelonephritis include the following:
    • Fever (Often, the temperature is very high.)
    • Chills
    • Nausea and vomiting
    • Costovertebral angle (CVA) or flank pain

Physical

A thorough physical examination is recommended, with particular attention to the abdomen.

  • CVA tenderness may be present.
  • Suprapubic tenderness may be present.
  • The fetal heart rate should be noted.
  • Pelvic examination is strongly recommended in all patients (with the exception of the third-trimester patient with bleeding) to rule out vaginitis or cervicitis.

Causes

  • Escherichia coli (most common, in as many as 70% of cases)
  • Group B Streptococcus (10%)
  • Klebsiella or Enterobacter species (3%)
  • Proteus species (2%)3

More on Pregnancy, Urinary Tract Infections

Overview: Pregnancy, Urinary Tract Infections
Differential Diagnoses & Workup: Pregnancy, Urinary Tract Infections
Treatment & Medication: Pregnancy, Urinary Tract Infections
Follow-up: Pregnancy, Urinary Tract Infections
References
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References

  1. [Guideline] American Academy of Pediatrics and American College of Obstetricians and Gynecology. Guidelines for Perinatal Care. American Academy of Pediatrics. 6th ed. 2007.

  2. Duarte G, Marcolin AC, Quintana SM, Cavalli RC. [Urinary tract infection in pregnancy]. Rev Bras Ginecol Obstet. Feb 2008;30(2):93-100. [Medline].

  3. [Guideline] Nicolle LE, Bradley S, Colgan R, Rice JC, Schaeffer A, Hooton TM. Infectious Diseases Society of America guidelines for the diagnosis and treatment of asymptomatic bacteriuria in adults. Clin Infect Dis. Mar 1 2005;40(5):643-54. [Medline].

  4. Smaill F. Asymptomatic bacteriuria in pregnancy. Best Pract Res Clin Obstet Gynaecol. Jun 2007;21(3):439-50. [Medline].

  5. Hill JB, Sheffield JS, McIntire DD, Wendel GD Jr. Acute pyelonephritis in pregnancy. Obstet Gynecol. Jan 2005;105(1):18-23. [Medline].

  6. Mazor-Dray E, Levy A, Schlaeffer F, Sheiner E. Maternal urinary tract infection: is it independently associated with adverse pregnancy outcome?. J Matern Fetal Neonatal Med. Feb 2009;22(2):124-8. [Medline].

  7. Vazquez JC, Villar J. Treatments for symptomatic urinary tract infections during pregnancy. Cochrane Database Syst Rev. 2000;CD002256. [Medline].

  8. Gilstrap LC 3rd, Ramin SM. Urinary tract infections during pregnancy. Obstet Gynecol Clin North Am. Sep 2001;28(3):581-91. [Medline].

  9. Krcmery S, Hromec J, Demesova D. Treatment of lower urinary tract infection in pregnancy. Int J Antimicrob Agents. Apr 2001;17(4):279-82. [Medline].

  10. Lucas MJ, Cunningham FG. Urinary infection in pregnancy. Clin Obstet Gynecol. Dec 1993;36(4):855-68. [Medline].

  11. Manka W, Solowiow R, Okrzeja D. Assessment of infant development during an 18-month follow-up after treatment of infections in pregnant women with cefuroxime axetil. Drug Saf. Jan 2000;22(1):83-8. [Medline].

  12. Miller JM, Raimer KA. Urinary tract infection and pyelonephritis in pregnancy. In: Obstetrics and Gynecologic Infectious Disease. 1994:283-93.

  13. Schieve LA, Handler A, Hershow R, Persky V, Davis F. Urinary tract infection during pregnancy: its association with maternal morbidity and perinatal outcome. Am J Public Health. Mar 1994;84(3):405-10. [Medline].

  14. Sweet RL, Gibbs RS. Urinary tract infection. In: Infectious Disease of the Female Genital Tract. 3rd ed. 1995:429-64.

  15. Zinner SH. Management of urinary tract infections in pregnancy: a review with comments on single dose therapy. Infection. 1992;20 Suppl 4:S280-5. [Medline].

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Further Reading

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Keywords

UTI in pregnancy, urinary tract infection in pregnancy, UTI symptoms, UTI treatment, complications of UTI in pregnancy, UTI causes, bacteriuria, UTI, bacterial infection, vesicoureteral reflux, acute pyelonephritis, urinary stasis, low birth weight, prematurity, premature labor, hypertension, preeclampsia, maternal anemia, amnionitis, cystitis, Escherichia coli, E coli, Klebsiella species, Proteus species, Enterobacter species

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Contributor Information and Disclosures

Author

Allison M Loynd, DO, Resident Physician, Department of Emergency Medicine, Wayne State University School of Medicine, Detroit Receiving Hospital
Allison M Loynd, DO is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, and Emergency Medicine Residents Association
Disclosure: Nothing to disclose.

Coauthor(s)

Adam J Rosh, MD, Assistant Professor, Department of Emergency Medicine, Wayne State University/Detroit Receiving Hospital
Adam J Rosh, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Michael S Beeson, MD, MBA, FACEP, Professor of Emergency Medicine, Northeastern Ohio Universities College of Medicine and Pharmacy; Attending Faculty, Summa Health System
Michael S Beeson, MD, MBA, FACEP is a member of the following medical societies: American College of Emergency Physicians, Council of Emergency Medicine Residency Directors, National Association of EMS Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Mark Zwanger, MD, MBA, Assistant Professor, Department of Emergency Medicine, Thomas Jefferson University
Mark Zwanger, MD, MBA is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and American Medical Association
Disclosure: Medicines Company Consulting fee Consulting; Pfizer Salary Employment

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Pamela L Dyne, MD, Professor of Clinical Medicine/Emergency Medicine, David Geffen School of Medicine at UCLA; Attending Physician, Department of Emergency Medicine, Olive View-UCLA Medical Center
Pamela L Dyne, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

 
 
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