E. coli Infection (Diarrhea and UTI) in Pregnancy, Symptoms and Dangers

What is E. coli?

E. coli or Escherichia coli are normal inhabitants of the human intestinal tract and vagina. Of the many strains of E. coli, most are harmless, but certain species can cause serious illnesses of the digestive and genitourinary system. Diarrhea or urinary tract infection (UTI) caused by E. coli may become severe at any time but such infections occurring during pregnancy may be dangerous for both mother and baby.

Diarrhea caused by E coli

E coli type 157:H7 is a virulent strain of E coli that has been the cause of several severe outbreaks of diarrhea. E coli O157:H7 bacteria are normally found in the intestines of cattle, poultry, and other animals. A new European strain of E coli known as Shiga toxin-producing E coli O104 (STEC O104) has been responsible for a recent deadly outbreak in Europe, particularly in Germany.


Picture of E.coli bacilli (Wikimedia Commons)

Contaminated food and water are common sources of E coli causing diarrhea. Foods that may pose a risk are undercooked meat, unpasteurized milk, and raw vegetables and fruits. All pregnant women, and particularly those traveling to developing countries, should be especially careful about what and where they eat as E coli is the most common cause of traveler’s diarrhea.

Symptoms of E.coli Diarrhea

Abdominal cramping and loose motion are the characteristic symptoms which may develop within a few hours or after several days of ingesting the bacteria. In severe cases, bloody diarrhea may occur. Most people recover within a few days but pregnant women are at increased risk of developing serious complications such as hemolytic uremic syndrome (HUS) which may lead to kidney failure and death in extreme cases. The main danger of diarrhea in pregnancy is dehydration which can harm the baby. Complications may include preterm delivery and low birth weight babies.

E.coli Urinary Tract Infection (UTI)

All women, and particularly pregnant women, are at risk of developing UTI. The most common causative organism is E coli, accounting for 80 to 90% of infections. The physiologic changes in pregnancy predispose women to UTI. Reduced immunological status during pregnancy may also contribute.

UTI can present as asymptomatic bacteriuria (bacteria in the urine), where patients have no symptoms, yet may have significant bacteriuria, which is defined as finding more than 105 colony-forming units per mL. Asymptomatic bacteriuria is common during pregnancy hence routine screening should be done and antibiotic therapy started on finding significant bacteria in the urine. Urine culture at the first prenatal visit or between 12 to 16 weeks of pregnancy is recommended in pregnant women. A repeat urine culture should be done in the third trimester. If left untreated, asymptomatic bacteriuria may develop into acute cystitis or pyelonephritis.

Symptoms of E.coli UTI

  • Frequency of urine.
  • Urgency.
  • Painful micturition (urination).
  • Burning sensation while passing urine.
  • Blood or pus in urine.
  • Foul smelling urine.
  • Fever.
  • Chill.
  • Nausea.
  • Vomiting.
  • Abdominal pain and backache.

Recurrence of UTI caused by E coli is common in pregnant women. Appropriate antibiotic therapy for 7 to 10 days may decrease the risk of recurrence. A repeat culture after completion of treatment can confirm successful treatment. Re-infection is a possibility and may be prevented by a daily dose of antibiotics.

Dangers of E coli Infection in Pregnant Women

  • Miscarriage.
  • Intrauterine growth retardation.
  • Preterm birth.
  • Low birth weight babies.
  • Pregnancy-induced hypertension.
  • Preeclampsia.
  • Anemia.
  • Amnionitis.

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