URINARY TRACT INFECTIONS IN PREGNANCY

REBECCA B. SINGSON, M.D, FPOGS

 

Urinary tract infections (UTI) are one of the most common infections that women consult their doctor for. When you are pregnant, you are particularly more susceptible to urinary tract infections, the incidence being as high as 8 percent (8%).  

WHY ARE UTI’s MORE COMMON IN PREGNANT WOMEN?

There are several reasons for this. From the 6th week  of gestation onwards and especially during weeks 22 to 24, the higher levels of the hormone progesterone  relaxes the muscles of your ureter, (the tube connecting the kidney to the bladder) causing it to stretch and dilate in 90% of the time, a condition known as hydronephrosis of pregnancy. Your growing uterus may also compress the ureters, making it difficult for urine to flow through them as quickly and freely as it normally does. Then later in pregnancy, the baby presses on your bladder, making it hard to empty it completely when you pee. The result of these changes makes it longer for urine to pass through your urinary tract, giving bacteria more time to multiply and attach to the lining of the bladder before being flushed out.1 It also does not help that up to 70 percent of pregnant women allow sugar to pass through the tubules of the kidney (glucose is normally sieved and saved). This encourages bacterial growth in the urine; add to that the effect of increased hormones passing out through the urine like progestins and estrogens which may lead to a decreased ability of the lower urinary tract to resist invading bacteria, and you have the ingredients increased susceptibility to infection during pregnancy.

There are actually 3 clinical presentations of UTI in pregnancy: asymptomatic bacteriuria, acute cystitis and acute pyelonephritis

ASYMPTOMATIC BACTERIURIA

As much as 10% of pregnant women can actually have urinary tract infection without showing signs and symptoms.4.5 That is why it is recommended that on the 1st prenatal check-up, your doctor should subject you to a routine urine culture or urine gram stain since a urinalysis by itself may not reveal an infection. A finding of >100,000 cfu/ml with one or more organisms in two consecutive mid-stream urine specimens or one catheterized urine specimen clinches the diagnosis. 

It is important to recognize and treat asymptomatic bacteriuria during pregnancy because not doing so can have disastrous results for you. It can lead to the development of symptomatic cystitis in approximately 30 percent of the time and can lead to the development of pyelonephritis (the infection ascending to your kidneys) in up to 50 percent.4 Asymptomatic bacteriuria is associated with an increased risk of intrauterine growth retardation and low-birth-weight infants.

Treatment should be initiated once asymptomatic bacteruria is detected. The choice of antibiotic should address the most common infecting organisms and at the same time be also be safe for you and your baby. Historically, ampicillin has been the drug of choice, for UTI in pregnancy but due to increasing resistance, this drug is no longer recommended.8 Nitrofurantoin (Macrodantin) is a good choice because it is highly concentrated in the urine. Alternatively, cephalosporins such as cephalexin and cefuroxime are well tolerated and are effective in treating the important organisms. Fosfomycin (Monurol) is a new antibiotic that is taken as a single dose. Sulfonamides can be taken during the first and second trimesters but, during the third trimester, the use of sulfonamides carries a risk that your baby may develop kernicterus (brain damage from excessive jaundice), especially if your baby is premature. There are other common antibiotics that you should be extremely wary about taking while you are pregnant (e.g., fluoroquinolones and tetracyclines) because of possible toxic effects on your baby. A seven- to 10-day course of antibiotic treatment is usually sufficient to eradicate the infecting organism(s). Some authorities have advocated shorter courses of treatment–even single-day therapy. Fosfomycin is effective when taken as a single, 3-g sachet.

After completing treatment, you are required to have a repeat culture to check if bacteriuria has been successfully eradicated.

ACUTE CYSTITIS

Acute cystitis is distinguished from asymptomatic bacteriuria if you are experiencing other symptoms such as painful urination (dysuria), frequent urination (urgency), and even blood in the urine (called hematuria), without any fever or evidence of systemic illness. Up to 30 percent of patients with untreated asymptomatic bacteriuria later develop symptomatic cystitis.6  It is also vital to treat acute cystitis while you are pregnant to prevent ascent of the infection to the kidneys.

The following antibiotics are recommended for acute cystitis in pregnancy:

  • Cephalexin  250 mg two or four times daily
  • Erythromycin  250 to 500 mg four times daily
  • Nitrofurantoin  50 to 100 mg four times daily
  • Amoxicillin-clavulanic acid  250 mg four times daily
  • Fosfomycin (Monurol)  One 3-g sachet
  • Trimethoprim-sulfamethoxazole160/180 mg twice daily (to be avoided during the 1st and 3rd trimester of pregnancy)11.12.13
  • Treatment is recommended for 7-10 days because shorter treatment regimens have resulted in recurrence of infection.

ACUTE PYELONEPHRITIS

Acute pyelonephritis can occur in 2% of pregnant women and is diagnosed when the presence of bacteriuria is accompanied by fever, chills, nausea, vomiting and flank pain. Symptoms of lower tract infection (i.e., frequency and dysuria) may or may not be present. It is a serious systemic illness that can progress to maternal sepsis, preterm labor and premature delivery. Up to 23 percent of these women have a recurrence of infection during the same pregnancy.10

Early, aggressive treatment is important in preventing complications from pyelonephritis. Hospitalization, although often indicated, is not always necessary. However, hospitalization is indicated for patients who are exhibiting signs of sepsis, who are vomiting and unable to stay hydrated, and who are having contractions. However, if you are able to take oral antibiotics and there are no signs and symptoms of sepsis, you may be treated as an out-patient. Treatment duration is 14 days. 6

WHAT HAPPENS IF MY UTI REMAINS UNTREATED DURING PREGNANCY?

Not treating a UTI during gestation can have devastating maternal and neonatal complications for you. Aside from the possibility asymptomatic bacteriuria developing to cystitis which may progress to pyelonephritis, it may also lead to intrauterine growth retardation and low birth weight infants. 4.7  A study by Schieve and associates shows that the presence of UTI was associated with premature labor (labor onset before 37 weeks of gestation), hypertensive disorders of pregnancy (such as pregnancy-induced hypertension and preeclampsia), anemia (hematocrit level less than 30 percent) and amnionitis 14 While this does not prove a cause and effect relationship, randomized trials have demonstrated that antibiotic treatment decreases the incidence of preterm birth and low-birth-weight infants.15  In addition, acute pyelonephritis has been associated with anemia.16

Disastrous outcomes for your baby aside from the risk of low-birth weight may be sepsis and pneumonia (specifically, group B streptococcus infection).17,18 UTI also increases the risk of prematurity (less than 37 weeks of gestation at delivery) and preterm, low-birth-weight infants (weight less than 2,500 g and less than 37 weeks of gestation at delivery)14.

WHAT CAN I DO TO AVOID UTI?

Majority of UTIs are caused by the bacteria, E. coli, which comes from the anus, contaminating and ascending up to your bladder to cause infection. The following tips will help you therefore prevent UTIs:

  1. After a bowel movement, wash and wipe yourself in a front to back direction to prevent bacteria from the stools from contaminating the urethra. Use your forefinger and middlefinger for the vaginal area and the ring and pinky fingers for the anal area to avoid contamination.
  2. Wash with lactic acid based vaginal wash (not soap since it is the wrong ph for the vaginal) before intercourse and urinate immediately after intercourse to prevent the organism from ascending through the ureter to the bladder.
  3. Never douche during pregnancy. Not only does it mechanically remove your protective bacteria, it can be potentially fatal since it  can cause air embolism. 4. Avoid feminine sprays or powders and soaps that can irritate your urethra and genitals and make them a better breeding ground for bacteria. And don’t use douches during pregnancy.
  4. Never ignore your urge to pee. Keep the urine in the bladder encourages bacterial multiplication and increases the chances of the bacteria adhering to the lining of the bladder causing infection.
  5. Drink plenty of water, at least eight 8-ounce glasses a day to keep urine dilute.
  6. Drink cranberry juice. Studies show that cranberry juice can reduce bacteria levels and discourage new bacteria from taking hold in the urinary tract. (Drinking cranberry juice won’t cure an existing infection, though, so if you’re having symptoms, you still need to see your doctor immediately to get a prescription for antibiotics.) 19-20

Recommended doses range from 90 to 480 milliliters (3 to 16 ounces) of cranberry cocktail twice daily, or 15 to 30 milliliters of unsweetened 100% cranberry juice daily. 300 milliliters per day (10 ounces) of commercially available cranberry cocktail (Ocean Spray®) has been used in well-designed research.

Other forms of cranberry used include capsules, concentrate and tinctures. Between one and six 300 to 400 milligram capsules of hard gelatin concentrated cranberry juice extract, twice daily by mouth, given with water 1 hour before meals or 2 hours after meals has been used. One and a half ounces of frozen juice concentrate.21

UTIs during pregnancy are a common cause of serious maternal and perinatal morbidity. However,  with appropriate screening and treatment, you can limit its morbidity and avoid the dreaded complications.

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