Urinary Tract Infection (UTI)

What is a urinary tract infection?

A urinary tract infection or UTI is a bacterial infection in the urinary system. An infection in the bladder is called cystitis and an infection that has moved up the urinary tract into the kidneys is called pyelonephritis.

Women in general are prone to urinary tract infections, with up to half of women having at least one infection during their lifetime. Women are not necessarily more prone to infections during pregnancy but if an infection does occur, it is more likely to be pyelonephritis (kidney infection) and to reoccur.

How common is a urinary tract infection during pregnancy?

One to two percent of pregnant women will get cystitis, or an infection of the bladder, during pregnancy. A similar number of women will develop pyelonephritis, which is a more serious infection that affects the kidneys.

More commonly, women are found to have bacteria in their urine by a routine screen at the first prenatal visit. This is not considered to be an infection but if left untreated it can cause either a UTI or pyelonephritis in 30 to 40% of women.

How is a urinary tract infection during pregnancy diagnosed?

Most women are diagnosed with asymptomatic bacteriuria during pregnancy. This means that bacteria are found in the urine by a routine screening test but there are no signs of infection. It is generally recommend to treat women with asymptomatic bacteriuria because of the high chance that a symptomatic infection will occur and because of the known risks that an infection can cause to the pregnancy.

If a bladder infection does occur, the symptoms of the infection may include any of the following:

• Pain or cramping in the lower part of the abdomen
• Pain or burning when you urinate
• Need to urinate more frequently and in small amounts
• Small amounts of blood in the urine
• Difficulty starting to urinate

If the infection has moved up into the kidneys then it is not uncommon to feel ill, have a fever higher than 100.4 degrees F, and have nausea and/or vomiting. Constant pain in the mid back area may also be a sign of pyelonephritis.

To confirm a UTI, a urine sample is needed. A basic check of the sample is usually performed in the clinic and if there are signs of an infection, it is sent to a laboratory for more detailed testing. Part of the laboratory test results will be available within an hour or two but the full test results take a minimum of 48 hours. If the preliminary test indicates an infection, then antibiotics will be started before the final results are available.

Does a urinary tract infection cause problems during pregnancy?

Urinary tract infections during pregnancy are more likely to develop into pyelonephritis, which is a more serious form of a UTI. Women who have pyelonephritis during pregnancy are more likely to require hospitalization for treatment with IV antibiotics and to be monitored for preterm labor.

Urinary tract infections, especially pyelonephritis, can lead to preterm labor by causing irritation of the uterus. If this occurs before 37 gestational weeks, then it increases the chances of preterm delivery and having a low birth weight baby.

Does a urinary tract infection during pregnancy cause problems for the baby?

The urinary tract infection itself does not cause problems for the baby but if the infection stimulates labor prior to 37 gestational weeks, then it puts the baby at risk for complications of prematurity. These include low-birth weight and an increased risk of death.

What to consider about taking medications when you are pregnant or breastfeeding:

You should think about:

• The risks to yourself and your baby if you do not treat the UTI
• The risk of not treating your UTI if you stop taking your antibiotic before the full course has been completed
• The risks and benefits of each medication you use when you are pregnant
• The risks and benefits of each medication you use when you are breastfeeding

What should I know about using medication to treat a urinary tract infection during pregnancy?

Antibiotics are usually given for seven days to treat both asymptomatic bacteriuria and bladder infections. Pyelonephritis is usually treated with IV antibiotics in the hospital until the fever is gone for at least 48 hours. At this time, the IV antibiotic is stopped and an oral antibiotic is given for 10 to 14 days.

Women that have more than two UTIs in pregnancy may be treated with a daily antibiotic to prevent additional infections from occurring. For women who are prone to getting UTIs after having sexual intercourse, a dose of an antibiotic taken after having sex can be used to prevent a UTI.

Who should NOT stop taking medication for a urinary tract infection during pregnancy?

Once you start taking an antibiotic for a UTI, the entire antibiotic course needs to be finished even if you are feeling better. As many as 30% of women will continue to have bacteria in their urine even after completing the antibiotics and this number increases if the antibiotics are not completed. The more infections that are partially treated causes higher bacteria resistance to specific antibiotics, which makes them ineffective. For this reason and to increase the chances of completely destroying all of the bacteria in the urine, it is important to always complete the course of antibiotics. If you have any concerns about the antibiotic or its side affects you should discuss these with your health care provider and not just stop taking the medication.

What should I know about choosing a medication for a urinary tract infection during pregnancy?

A large number of antibiotics are safe for use during pregnancy but there are a few that are generally avoided during pregnancy. Fluoroquinolones, like Cipro, and tetracyclines, like doxycycline, are not used in pregnancy. Exposure to tetracyclines while in the womb can cause a babys teeth to be a bright yellow color when they grow in and can affect their bone growth. It can also cause liver problems for the mom when it is taken in pregnancy. Fluoroquinolones can affect the babies developing muscles and joints if it is used in pregnancy.

It is recommended to avoid using sulfonamides (ie Bactrim) and nitrofurantoin (Macrobid) in the first trimester of pregnancy because one study linked them to congenital birth defects. These include heart defects and cleft lip with cleft palate (a split in the upper lip and palate). Trimethoprim, which is one of the medications in Bactrim, has also been linked to neural tube defects (abnormal spine or brain development) when it is used during the first trimester.  Sulfonamides are also avoided close to delivery because they can increase the levels of bilirubin in the newborn, which is what causes jaundice.

However, if an infection is severe enough and any of these antibiotics are the only treatment option because of the type of bacteria, they may be considered for use in pregnancy. If this occurs, it is important to discuss the risks and the benefits of the treatment with your health care provider.

You may find Pregistrys expert reports about the individual medications to treat UTI here. Additional information can also be found in the sources listed at the end of this report.

What should I know about taking a medication for my urinary tract infection when I am breastfeeding?

Most antibiotics are safe for use while nursing with only a few exceptions. Trimethoprim-sulfamethoxazole (Bactrim) is generally avoi
ded during the first two months of nursing because there is a small chance that it can increase the infants bilirubin levels. If this occurs it can cause the baby to develop severe jaundice. Tetracycline is also avoided because it may cause the babies teeth to be a bright yellow color when they grow in. However, this risk is low because only small amounts are passed to the infant in breastmilk and the calcium in the milk limits the infants absorption of any of the antibiotic.

What alternative therapies besides medications can I use to treat my urinary tract infection during pregnancy?

Antibiotics are the only way to treat a bacterial infection so there are no alternative treatments for this condition.

Phenazopyridine (AZO, Uristat) can be taken to decrease the symptoms of a UTI and has not been reported to cause congenital anomalies. However, phenazopyridine will not treat or cure an infection so it is not an alternative to an antibiotic.

Drinking cranberry juice or taking cranberry tablets to prevent a UTI may be tried but there is conflicting evidence about whether it will really help or not. Some women who are prone to getting UTIs have seen a decrease in the number of UTIs they get but other women have not seen any improvement. Drinking cranberry juice in pregnancy is not harmful so it may be tried if you are prone to getting UTIs.

What can I do for myself and my baby when I have a urinary tract infection during pregnancy?

The best thing you can do for yourself and your baby if you get a UTI in pregnancy is to take the entire course of antibiotics. Preventing another UTI may not be possible but trying the following may help reduce your chances:

• Stay well hydrated
• After urinating, wipe from front to back (this decreases bacteria getting to the urethra from the rectum)
• Urinate after having sex

If you do have a UTI, are less than 37 gestational weeks pregnant, and develop signs of preterm labor it is important to call your healthcare provider right away. Signs of preterm labor include:

• Low back ache that may come and go every few minutes
• Contractions every 10 minutes or more frequently
• The feeling of menstrual type cramps
• Leaking fluid from the vagina or bleeding
• Pelvic pressure

Resources for urinary tract infection during pregnancy:

For more information about Urinary Tract Infection during and after pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or visit the following links:

• March of Dimes Genital and Urinary Tract Defects
• American College of Obstetrics and Gynecology Urinary Tract Infections UTIs
• WebMD Pregnancy Urinary Tract Infection