Infections of the Urinary Tract

Your urinary tract and renal system are delicate structures which are crucial in your body’s ability to dispose of its waste products. Without this system, one dies. With a damaged system, one suffers. Ideally, the product of this system, urine, should be “sterile” (that is, contain no bacteria). Some bacteria are capable of damaging the lining of the urinary tract and the very delicate filter in the kidney. Damage to the filtration system of the kidney may lead to permanent kidney disease.

5-10% of pregnant women will have bacteria in the urine without any symptoms (called “asymptomatic bacteruria”). Because the female urethra is so short (half the length of the male urethra) women are much more prone to urinary tract infections than men. Urinary tract infections are somewhat common in pregnant women. Approximately 2% of women will get an acute symptomatic urinary tract infection during pregnancy. Pregnant women are more likely than non-pregnant women to get urinary tract infections for 3 reasons:

  • After urinating, pregnant women have more “residual” (leftover) urine left in the bladder. This urine can promote the growth of bacteria.
  • Due to certain hormones in pregnancy, the entire urinary tract is more soft, loose and flaccid. This “lack of tone” slows down the usual outflow of urine and may allow backflow up towards the kidneys. It is also the reason there is more “residual” urine in the bladder.
  • The kidneys allow more sugar to pass from the blood into the urine during pregnancy. Bacteria like sugar.

Urinary tract infections (“UTI”) during pregnancy are more concerning than those that occur in non-pregnant women for 2 reasons. 1) Bladder infections are more likely to ascend into the kidneys, and 2) Infections of the urinary tract, if untreated, may increase the chance of premature labor and delivery.

Infections of the lower urinary tract (principally the bladder) usually cause symptoms:

  • burning with urination (“dysuria”)
  • frequent urination (“frequency”)
  • a feeling of needing to urinate when you cannot (this is called “urgency”)

If you have these symptoms, call your midwife or doctor. Frequency and urgency are common symptoms in pregnancy even if the bladder is not infected. If an infection is suspected, your urine should be tested for the presence of bacteria (see UA and C&S). If you have an infection, you will probably need some antibiotics to keep the bacteria from ascending into the kidneys. Not only can bacteria damage the kidneys, but the inflammation may cause the uterus to begin contracting.

If you have repeated urinary tract infections, or have a history of repeated infections, you may need to be on a daily, low-dose antibiotic for “suppression” of bacterial growth. Often the antibiotic, nitrofurantoin, is used for this. It is a generally safe antibiotic that passes well into the urine.

If bacteria does ascend into the kidney, it is usually the right kidney which is infected in pregnant women. If you experience pain on the right side of the back, up high, underneath the rib cage, call your doctor or midwife. Sometimes, this pain is associated with fever and chills. If left untreated, the kidney can be permanently damaged.