bladder-infection-pregnancy.jpgPregnant women may be more susceptible to urinary tract infections and bladder infections. The increased risk of infection is thought to be associated with the relaxation of muscles as progesterone levels increase during pregnancy. Diagnosing and treating bladder infections during pregnancy is extremely important as infection may lead to pregnancy complications.

Pregnancy Complications and Bladder Infection
Pregnant women with symptoms of a bladder infection should report the symptoms to the primary care provider immediately. Urinary tract and bladder infections may increase the risk of premature labor, premature delivery, lower than normal fetal birth weight and perinatal mortality. In one study of more than 50,000 pregnancies, showed women with bacterial infections of the urinary tract or bladder had a significantly higher risk of perinatal mortality.

Not all urinary tract and bladder infections present with symptoms, which makes diagnosis in pregnant women more difficult. Between 12 and 16 weeks gestation, pregnant women typically undergo urine cultures for bacterial infection. Urine cultures collected during a routine prenatal visit are tested for bacterium in a lab setting. If bacterium is present, pregnant patients are treated with antibiotics considered safe for use in pregnancy.

Antibiotics and Pregnancy

Treating a bladder infection during pregnancy requires using antibiotics considered safe for use in pregnant women. Older antibiotics are more likely to have been tested on pregnant women as pregnant women were allowed to participate in drug trials before rules of exclusion were adopted. Antibiotics are categorized in terms of safety during pregnancy. In most cases, doctors will prescribe antibiotics in category B if a pregnant women tests positive for a bladder infection. Some of the antibiotics falling into category B include:


  • Penicillins
  • Cephalosporins
  • Fosfomycin

Not all category B antibiotics are considered safe during pregnancy. Nitrofurantoin and sulfonamides both fall into category B, but they are contraindicated for use in the first trimester and possibly throughout pregnancy. Some researchers believe the tests completed on these antibiotics were misrepresented as testing involved only a small number of infants exposed to the drugs. However, additional studies regarding increased risk of hemolytic anemia and increased unbound bilirubin in infants suggest doctors should choose another form of antibiotic. Other antibiotics that should be avoided during pregnancy include:

  • Trimethoprim (first trimester)
  • Fluoroquinolones
  • Tetracyclines

List of Antibiotics Prescribed for Bladder Infections in Pregnancy
Pregnant women may be prescribed one of the following antibiotics during pregnancy. It is important to complete the entire course of antibiotics to reduce the risk of future bladder infections in pregnancy.

  • Nitrofurantoin – 100 mg twice a day for five days
  • Amoxicillin – 500 mg twice a day for three to seven days
  • Amoxicillin clavulanate – 500 mg twice a day for three to seven days
  • Cephalexin – 500 mg twice a day for three to seven days
  • Fosfomycin – 3,000 mg (one dose)

Bladder infections in pregnancy can be treated effectively with a short, safe course of antibiotics. If you are experiencing symptoms of a bladder infection, including burning during urination, painful urination or frequent strong urges to urinate, talk with your obstetrician about the symptoms.