Lower UTI in Pregnancy

Comments from Expert Advisory Committee

Send MSU for culture.
Nitrofurantion should be avoided after 36 weeks due to risk of neonatal haemolysis.
Refer to local resistance patterns for empiric therapy where available and refer to MSU results. Amoxicillin resistance is common – only use if susceptibility data available.
Review empirical treatment with results of MSU culture and susceptibility.
Trimethoprim should not be prescribed for pregnant women with established folate deficiency, low dietary folate intake, or women taking other folate antagonists.
Note guidelines on Asymptomatic Bacteriuria in Pregnancy
If acute pyelonephritis is suspected, consider referral to hospital. Consider acute pyelonephritis/ upper UTI when:
- Pain in the loin which radiates to the iliac fossa and suprapubic area.
- Sudden onset general systemic disturbance with fever, rigors, vomiting.
- Tenderness and guarding over the kidney.

Treatment

Drug	Dose	Duration	Notes
Nitrofurantoin Immediate Release Capsules	50mg-100mg every 6 hours	7 days	Avoid after 36 weeks due to risk of neonatal haemolysis. Immediate/ Prolonged Release should be stated on the prescription (¹see note below on formulation difference)
OR
Nitrofurantoin Prolonged Release Capsules	100mg every 12 hours	7 days
Amoxicillin*	500mg every 8 hours	7 days	*If known to be susceptible
2nd choice option
Cefalexin	500mg every 8 hours	7 days
Alternative (if resistance to the above agents is suspected or if adherence to the above treatment course would be particularly problematic)
Fosfomycin	3g	Single dose	Fosfomycin should only be used after a careful risk benefit assessment. Data in pregnancy is limited but to date has not indicated teratogenicity. Manufacturer advises that Fosfomycin should only be used during pregnancy, if clearly necessary. Fosfomycin should ideally be taken at night, on an empty stomach, and empty bladder to maximise absorption and effectiveness.

*Seek specialist/microbiologist advice in case of severe penicillin allergy in pregnant patients if nitrofurantoin is not an option.

¹Two nitrofurantoin formulations are available: nitrofurantoin immediate release capsules (Macrodantin®) and nitrofurantoin prolonged release capsules (MacroBid®). For the treatment of infection the prolonged release capsules are dosed twice daily whilst the standard capsules are dosed four times daily.

Patient Information

Visit HSE A-Z website for further information on urine urinary tract infections in pregnancy.
Bumps – Best use of medicines in pregnancy (from UK Teratology Information Service)
Visit HPSC Information Leaflets pages for the General Public, (MRSA, CRE, etc)

Safe Prescribing (visit the safe prescribing page)

Doses are oral and for adults unless otherwise stated
Dosing in children quick reference dosage/weight guide
Penicillin allergy – tips on prescribing in penicillin allergy
Renal impairment dosing table
Safety in Pregnancy and Lactation
Drug interactions table. Extensive drug interactions for clarithromycin, fluoroquinolones, azole antifungals and rifampicin. Many antibiotics increase the risk of bleeding with anticoagulants.
Visit the Health Products Regulatory Authority (HPRA) website for detailed drug information (summary of product characteristics and patient information leaflets). Dosing details, contraindications and drug interactions can also be found in the Irish Medicines Formulary (IMF) or other reference sources such as British National Formulary (BNF) / BNF for children (BNFC).

Reviewed May 2022