Acute cystitis in pregnancy

Obtain a midstream urine sample for microscopy, culture and susceptibility testing before starting antibiotic therapy for pregnant patients with symptoms of cystitis. See Approach to empirical antibiotic choice for UTI in adults and Rationale for empirical therapy for acute cystitis in adults for a discussion of antibiotic choice.

When prescribing for pregnant patients, consider the safety of the antimicrobial in the individual patient.

For empirical therapy for acute cystitis in pregnancy, while awaiting the results of urine culture, usePhilipps, 2020Schulz, 2022The American College of Obstetricians and Gynaecologists (ACOG), 2023Wang, 2020:

1nitrofurantoin 100 mg orally, 6-hourly for 5 days123. For dosage adjustment in adults with kidney impairment, see nitrofurantoin dosage adjustment nitrofurantoin nitrofurantoin nitrofurantoin

OR

2cefalexin 500 mg orally, 12-hourly for 5 days. For dosage adjustment in adults with kidney impairment, see cefalexin dosage adjustment cefalexin cefalexin cefalexin

OR

3fosfomycin 3 g orally, as a single dose4. fosfomycin fosfomycin fosfomycin

Modify empirical therapy if culture and susceptibility testing indicates that the pathogen is resistant to the above regimens. If susceptibility is confirmed, suitable alternatives includeThe American College of Obstetricians and Gynaecologists (ACOG), 2023:

1amoxicillin 500 mg orally, 8-hourly for 5 days. For dosage adjustment in adults with kidney impairment, see amoxicillin dosage adjustment amoxicillin amoxicillin amoxicillin

OR

2amoxicillin+clavulanate 875+125 mg orally, 12-hourly for 5 days5. For dosage adjustment in adults with kidney impairment, see amoxicillin+clavulanate oral dosage adjustment. amoxicillin + clavulanate amoxicillin+clavulanate amoxicillin+clavulanate

If susceptibility is confirmed, trimethoprim can be considered in the second and third trimestersAndersen, 2013Muanda, 2018Yang, 2011. Because trimethoprim affects folate metabolism, some centres recommend high-dose folate supplementation with trimethoprim; however, the need for high-dose folate supplementation beyond the first trimester, the optimal dose and duration is unclear – seek expert adviceAndersen, 2013. Use:

trimethoprim 300 mg orally, daily for 3 days. For dosage adjustment in adults with kidney impairment, see trimethoprim dosage adjustment. trimethoprim trimethoprim trimethoprim

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 pregnancyWidmer, 2015.

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) diseaseSchafer, 2020.

1 An alternative regimen is 100 mg 12-hourly for 5 days. This is from a study using Macrobid®, a slow-release formulation unavailable in Australia.Return
2 Avoid using nitrofurantoin close to delivery (after 37 weeks gestation, or sooner if early delivery is planned) because of the possible increased risk of neonatal jaundice and haemolytic anaemia.Return
3 Retrospective data suggest that nitrofurantoin is safe and effective for short-term treatment (5 to 7 days) of acute cystitis in patients with a glomerular filtration rate (GFR) of 30 mL/min or moreCunha, 2017Geerts, 2013Santos, 2016Singh, 2015.Return
4 At the time of writing, fosfomycin is not available on the Pharmaceutical Benefits Scheme (PBS). See the PBS website for current information.Return
5 Amoxicillin+clavulanate can be used during pregnancy but should be avoided in patients with preterm prelabour rupture of membranes (PPROM) because of a potential increased risk of neonatal necrotising enterocolitis.Return