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Obstetrics Simplified - Diaa M. EI-Mowafi

Urinary Tract Infection in Pregnancy



It is the presence of 100000 organisms/ml of the same species in two cultured fresh, mid-stream specimens of urine.


2-5% of pregnant women. If not treated 30% of them will develop symptomatic infections.


  • Symptomatic infections as cystitis and pyelonephritis.
  • Anaemia.
  • Hypertension.
  • Intrauterine growth retardation.
  • Pre-term delivery.


  • Ampicillin or cephalosporin 500 mg/ 6 hours for 10 days or
  • Nitrofurantoin 100 mg/6 hours.



It is inflammation of the renal pelvis and parenchyma.


30% in cases with asymptomatic bacteriuria and 1% in cases without.

Predisposing Factors during Pregnancy

  • Urine stasis during pregnancy due to:
    • Compression of the ureter by the gravid uterus against the pelvic brim particularly on the right side. So infection is more common on the right side.
    • Relaxation of the ureter by progesterone effect.
  • Increased urinary excretion of glucose and amino acids favours the growth of bacteria.

Causative Organisms

  • Escherichia coli (E.coli) (90%).
  • Klebsiella, streptococcus, staphylococcus, proteus, pseudomonas and others.



Started usually after 16 weeks in the form of:

  • malaise,
  • anorexia,
  • nausea and vomiting,
  • rigors,
  • dysuria,
  • urgency and frequency of micturition,
  • renal pain commonly on the right side.


  • Fever reaching 40oC,
  • rapid pulse,
  • tenderness in one or both renal angles (costovertebral angle).


  • Urine analysis: pus cells, organisms and proteins. Casts and RBCs may be present.
    • N.B. Presence of organisms without pus cells suggests contamination, while pus cells without organisms creates suspicion of tuberculosis.
  • Culture and sensitivity: for urine.
  • Blood picture: leucocytosis.

Differential diagnosis

  • Causes of acute abdomen as appendicitis, abruptio placentae and complications of pelvic tumours.
  • Causes of vomiting.


  • Chronicity: with recurrent infections. In these cases, plain X-ray and intravenous pyelography (IVP) should be done after delivery to exclude urinary stones. Chronic pyelonephritis may result in hypertension and renal failure later on .
  • Abortion, intrauterine foetal death, IUGR or premature labour may result.


  • Bed rest: light diet and plenty of fluids. Intravenous fluid may be needed if there is vomiting
  • Analgesics and antipyretics.
  • Alkalies: as potassium citrate to inhibit the growth of E.coli.
  • Antibiotics and chemotherapy: The following therapy is started until the result of culture and sensitivity is obtained.
    • Ampicillin 500 mg/ 6 hours, or
    • Nitrofurantoin 100 mg/ 6hours, or
    • Cephalosporins 500 mg/ 6 hours.
    • Treatment is continued for 7-10 days.