Uncomplicated UTI (urinary tract infection) in pregnancy

• if the women has fever or loin tenderness
  • suspect upper urinary tract infection and admit or seek urgent specialist opinion
• give paracetamol for symptomatic relief
• do not recommend urine alkalinizing agents or cranberry products
• send a urine sample for culture before starting antibiotic treatment
• prescribe antibiotics empirically
  • refer to local guidelines
    
    
  • if local guidelines are uavailable, suitable first-line antibiotics are (in order of preference) (1):
    • however see also notes below about use of trimethoprim and nitrofurantoin in pregnancy
      • nitrofurantoin 50 mg four times daily, or 100 mg (modified-release) twice daily, for 7 days
      • trimethoprim 200 mg twice daily, for 7 days
        • give folic acid 5 mg daily if it is the first trimester of pregnancy. Do not give trimethoprim if the woman is folate deficient, taking a folate antagonist, or has been treated with trimethoprim in the past year
      • cefalexin 500 mg twice daily, or 250 mg 6-hourly, for 7 days
      • amoxicillin 250 mg three times daily, for 7 days may occasionally be used if unable to treat with other suggested antibiotics. However resistance to amoxicillin makes it less effective as an empirical treatment option compared to those stated
        
        
    • if symptoms of UTI persist when sensitivities are known, treatment options are (in order of preference) (1):
      • amoxicillin 250 mg three times daily, for 7 days
      • nitrofurantoin 50 mg four times daily, or 100 mg (modified-release) twice daily, for 7 days
      • trimethoprim 200 mg twice daily, for 7 days (off-label use). Give folic acid 5 mg daily if it is the first trimester of pregnancy. Do not give trimethoprim if the woman is folate deficient, taking a folate antagonist, or has been treated with trimethoprim in the past year
      • cefalexin (500 mg twice daily, or 250 mg 6-hourly, for 7 days) may be used but is less preferred
        
        
• follow-up
  • ensure that there is patient follow up after 48 hours (or according to the clinical situation) to check response to treatment and the urine culture results.

Quinolones and tetracyclines should be avoided as empirical treatments. There are concerns about use of sulphonamides and trimethoprim in pregnancy:

• trimethoprim - theoretical teratogenic risk (folate antagonist); manufacturers advise avoid; BNF states first trimester is the trimester of risk. It is, however, widely used and probably safe in the second and third trimesters (2)
• sulphonamides - neonatal haemolysis and methaemaglobinaemia; BNF states third trimester is trimester of risk
• tetracyclines - avoid use during pregnancy; effects on skeletal development in animal studies if used during first trimester; dental discoloration and maternal hepatoxicity may occur if used during second or third trimesters
• quinolones - should be avoided during pregnancy; arthropathy in animal studies

Nitrofurantoin should not be used at term because of the risk of neonatal haemolysis - during the last few weeks may precipitate haemolytic anaemia due to glucose-6-phosphate dehydrogenase deficiency in the newborn

• BNF states third trimester is the trimester of risk associated with nitrofurantoin use

Consult local microbiology advice and latest edition of BNF for up-to-date guidance before definitive treatment.
Notes:

• about 1-2% of pregnant women suffer an acute lower UTI (cystitis) or upper UTI (pyelonephritis), with the former being more common
  • the most common infecting organisms is Escherichia coli (75-90 per cent); other infecting organisms include Proteus, Klebsiella, coagulase-negative staphylococci and Pseudomonas
• when the pregnant mother is very ill with acute pyelonephritis then there is a risk of preterm labour and even fetal loss. Thus hospital admission is recommended for these patients with intravenous antibiotics, hydration and analgesia. Treatment should be continued for two or three weeks
• about 15 % of women will have a recurrent UTI during pregnancy. Sometimes, a continuous low-dose prophylaxis throughout pregnancy is required in some women with recurrent UTI. These women require renal tract ultrasound scans, and review by a nephrologist or a urologist postnatally

Reference:

1. NHS Clinical Knowledge Summaries (Accessed 28/4/15). Uncomplicated UTI in pregnancy.