Urinary Tract Infection (UTI) in Pregnancy

Dr. Premitha Damodaran

Consultant Obstetrician & Gynaecologist

MBBS, MMED (Obst & Gynae)

Pantai Hospital Kuala Lumpur


What is UTI?

UTI (Urinary Tract Infection) is an infection of any part of the system involved in excreting urine i.e. the kidneys, the ureter (a tube that carries urine from the kidneys to the bladder), the bladder and the urethra(the tube from the bladder that is the outlet for the urine).

Why is UTI so common in women, especially in pregnancy?

UTI is 14 times more common in women than women because:

  • The urethra is shorter in women
  • The lower third of the urethra in women can become contaminated by bacteria and other organisms from the vagina and rectum
  • Intercourse can increase transfer of bacteria to the female urinary tract

Additional reasons for UTI in pregnancy are:

  • The progesterone hormone (which increases in pregnancy) relaxes the smooth muscles of the ureter causing urine to slow down. This increases infection risk.
  • The enlarging uterus puts additional pressure on the ureter and changes the angle of the urethra causing urine to stay longer the in the urinary tract which increases infection.
  • A pregnant lady has lowered immunity thus susceptible to infections.

What causes UTI?

UTI is caused by bacteria that enter the urinary system from the vagina, skin, bowel, blood and other sources. The commonest bacteria involved is E.Coli (80%) followed by Klebsiella, Pseudomonas, Enterobacter, Proteus and chlamydiae.

The bacteria then causes:

  • Asymptomatic bacteriuria which means there is bacteria in the urine without any symptoms. It is diagnosed if 2 consecutive urine samples show  presence of more than 100,000 bacterial organisms / ml. Untreated, this type of UTI increases the risk of acute cystitis (bladder infection) by 40% and pyelonephritis (kidney infection) by 25 – 30 %.
  • Acute cystitis (bladder infection) occurs when only the lower urinary tract (bladder / urethra) is involved. The risk in pregnancy is only 1%. Cystitis can become an upper urinary tract infection involving the kidney (pyelonephritis) in 15 – 50 % of the cases.
  • Acute pyelonephritis is the most common complication of UTIs in pregnant women – occurring in 2% of pregnancy. The triad of   fever, flank pain and tenderness, along with presence of bacteria in the urine are diagnostic.


What are the symptoms of UTI?

The symptoms of UTI include

  • An urgent need to urinate, dribbling of urine and frequent urination
  • Burning pain while passing  urine
  • Urine has blood or appears cloudy and flaky
  • Lower abdominal pains, cramps in the lower back
  • Retention of  urine
  • Fever with chills & rigors

What happens if one has UTI?

A small sample of urine (preferably a clean midstream sample) is taken. A simple bedside dipstick test shows presence of protein. A more definitive test involves sending the sample to the laboratory that carries out a full culture and sensitivity test. This test would reveal the bacteria involved and the antibiotics to which it is sensitive.

Antibiotic therapy is mandatory. A full course for 5 – 7 days should be taken even though improvements are usually seen in 48 hours. The antibiotics are important and will not harm the baby. It would be wise to repeat the urine culture to ensure the infection has been adequately treated.

Is the risk of UTI the same throughout pregnancy?

It is most common in the 2nd trimester (52%). The risk in the third trimester is about 46% while only 2% in the first trimester.

How will UTI affect the pregnancy?

If left untreated, UTI can cause kidney infections (pyelonephritis) which in turn can cause early deliveries (premature labour) and low birth weight babies.

Who are the women who are at more risk of UTI’s in pregnancy?

  • Women with diabetes in pregnancy
  • Preeclampsia during pregnancy
  • Caesarean deliveries (emergency)
  • Previous history of UTI’s
  • History of urethral reflux problems
  • History of previous surgery to kidney, ureter or bladder

How does one avoid getting UTI’s?

  • Drink at least 8 glasses of water a day
  • Wipe the vagina area from front to back
  • Empty bladder frequently
  • Empty bladder shortly before and after sex
  • Avoid douches and feminine deodorants
  • Wear cotton underwear
  • Avoid tight fitting clothing



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