Modification and duration of therapy for acute pyelonephritis in pregnancy
Modify therapy for acute pyelonephritis in pregnancy based on the results of culture and susceptibility testing.
If the results of susceptibility testing are not available by 72 hours after the initial empirical antibiotic dose, intravenous therapy is still required, and an aminoglycoside-based regimen was used initially, switch to ceftriaxone (as above).
Switch to an oral antibiotic regimen once the patient is clinically stable and able to tolerate and absorb oral therapy – see Guidance for intravenous to oral switch. Despite limited data, it is the consensus of the Antibiotic Expert Group that higher dosages of oral beta-lactam antibiotics should be used for acute pyelonephritis to ensure adequate antimicrobial exposure and activity against Enterobacterales (eg Escherichia coli)Heil, 2021Mponponsuo, 2023.
Oral therapy should be based on the results of culture and susceptibility testing. If susceptibility is confirmed, suitable regimens include:
1amoxicillin 1 g orally, 8-hourly. For dosage adjustment in adults with kidney impairment, see amoxicillin dosage adjustment amoxicillin amoxicillin amoxicillin
OR
2cefalexin 1 g orally, 6-hourly. For dosage adjustment in adults with kidney impairment, see cefalexin dosage adjustment cefalexin cefalexin cefalexin
OR
3amoxicillin+clavulanate 875+125 mg orally, 8-hourly1. For dosage adjustment in adults with kidney impairment, see amoxicillin+clavulanate oral dosage adjustment. amoxicillin + clavulanate amoxicillin+clavulanate amoxicillin+clavulanate
If susceptibility is confirmed, cefalexin can be used for pregnant patients who have had a nonsevere (immediate or delayed) hypersensitivity reaction to a penicillin2.
For pregnant patients who have had a severe (immediate or delayed)3 hypersensitivity reactionto a penicillin, seek expert advice for suitable regimens. In the second or third trimester of pregnancy, if susceptibility is confirmed, suitable regimens may includeAndersen, 2013Muanda, 2018Yang, 2011Lin, 2022:
1ciprofloxacin 500 mg orally, 12-hourly4. For dosage adjustment in adults with kidney impairment, see ciprofloxacin oral dosage adjustment ciprofloxacin ciprofloxacin ciprofloxacin
OR
1trimethoprim+sulfamethoxazole 160+800 mg orally, 12-hourly5. For dosage adjustment in adults with kidney impairment, see trimethoprim+sulfamethoxazole dosage adjustment. trimethoprim + sulfamethoxazole trimethoprim+sulfamethoxazole trimethoprim+sulfamethoxazole
Because trimethoprim affects folate metabolism, some centres recommend high-dose folate supplementation with trimethoprim+sulfamethoxazole; however, the need for high-dose folate supplementation beyond the first trimester, optimal dose and duration are unclear – seek expert adviceAndersen, 2013.
The total duration of therapy (intravenous + oral) for acute pyelonephritis in pregnancy is 7 to 10 days, based on data from nonpregnant patients. The duration of therapy depends on clinical response, antibiotic used and route of administrationBonkat, 2024McAteer, 2023National Institute for Health and Care Excellence (NICE), October 2018. Therapy duration of 7 days is reasonable if:
- intravenous therapy with a beta-lactam antibiotic (eg ceftriaxone) is used for the entire course
- ciprofloxacin or trimethoprim+sulfamethoxazole is used for oral continuation therapy.
For all other patients, the total duration of therapy (intravenous + oral) is 10 days.
Confirm the infection has resolved by repeating urine culture 1 to 2 weeks after treatment is completed. If persistent bacteriuria is identified, see Recurrent UTI and bacteriuria in pregnancy.
If Streptococcus agalactiae (group B streptococcus [GBS]) is detected in urine at any stage of pregnancy, intrapartum prophylaxis for GBS is usually indicated – see Prevention of neonatal Streptococcus agalactiae (group B streptococcus) disease.