What is the appropriate antibiotic choice for treating a UTI in a pregnant patient?

For treating a urinary tract infection (UTI) in a pregnant patient, the first-choice antibiotic is nitrofurantoin 100 mg modified-release twice daily for 7 days, but it should be avoided in the third trimester.

Second-choice antibiotics include cefalexin 500 mg twice daily for 7 days or amoxicillin 500 mg three times daily for 7 days, provided the urine culture shows susceptibility.

Before starting treatment, a mid-stream urine (MSU) sample should be sent for culture and sensitivity testing to guide antibiotic choice.

Urgent hospital admission is warranted if there are severe systemic symptoms or signs of complications such as pyelonephritis or sepsis, or if the patient cannot tolerate or adhere to treatment in primary care.

Specialist advice should be sought if there are recurrent UTIs during pregnancy, catheter-associated UTIs, atypical or resistant organisms, or underlying urinary tract abnormalities.

Patients should be advised to seek urgent medical review if symptoms worsen rapidly or do not improve within 48 hours of starting antibiotics.

Antibiotic choice should be reviewed once urine culture and susceptibility results are available, aiming to use narrow-spectrum antibiotics where possible.