Urinary Tract Infections in Pregnant Women

1. Asymptomatic bacteriuria increases the risk of acute cystitis, acute pyelonephritis, premature birth, and a low birth weight. Urine cultures should be performed at least once in the early stages of pregnancy (during the first obstetric visit or between weeks 12 and 16 of pregnancy) and treatment should be started if significant bacteriuria is detected.

Treatment according to the results of urine culture (as in cystitis) should last from 3 to 7 days. After discontinuation of treatment, follow-up urine cultures should be performed periodically to detect possible relapses (these affect a third of patients).

2. Cystitis: Diagnosis may be delayed due to the frequent occurrence of features typical for cystitis (frequency, urgency, lower abdominal discomfort) during normal pregnancy. The recommended oral treatment includes amoxicillin 500 mg tid; amoxicillin + clavulanic acid 625 mg bid; cephalexin (INN cefalexin) 250 to 500 mg qid; fosfomycin 3 g in a single dose; trimethoprim/sulfamethoxazole 160/800 mg bid (do not use in the first trimester or shortly before delivery).

Duration of treatment: 3 to 7 days. Urine cultures must be performed in every patient and the treatment regimen must be adjusted on the basis of the culture results.

3. Acute pyelonephritis affects from 1% to 2% of all pregnant women. It most frequently occurs during the second or third trimester due to impairment of the urinary flow. Typical clinical manifestations include high-grade fever, flank pain, frequently dysuria and vomiting (this may cause dehydration).

Treatment should be started in hospital as in nonpregnant patients. Note that fluoroquinolones are contraindicated in pregnant women due to their teratogenic effects.