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Antibiotics For UTI When Pregnant: Recommendations


Urinary-tract infection (UTI) is a common condition experienced in pregnancy. Physiological changes to the urinary tract during the pregnancy, such as dilation of the urethra and decreased bladder capacity, increase the risk of urinary infections or thrush-like problems. (Hebak, 2019).

UTI is an umbrella term that defines the bladder (cystitis), kidneys, or urethra infection. In this post, I am looking at recommended antibiotics for UTIs when a pregnant patient is affected by this condition.

UTI Common Symptoms

Common symptoms of UTI may include:

  • Difficulties/discomfort when urinating
  • Increased frequency of urination
  • Lower abdominal pain (lower stomach)
  • A strong smell of urine
  • Cloudy looking urine or urine that contains a blood
  • Feeling unwell

In contrast, asymptomatic bacteriuria, which is also possible in the pregnancy, is defined as the presence of the bacteria in the urine with no symptoms or signs of urinary tract infection.

UTI In Pregnancy: Test For Bacteria

It is recommended to test for bacteria before treatment with antibiotics for UTI in pregnancy is commenced. Tets for bacteria presence are usually performed by obtaining a midstream urine sample.

Certain patients may be offered an antibiotic, for example, a pregnant patient who was previously treated with an antibiotic, which may have led to the growth of resistant bacteria, or pregnant patients with previous test results.

The choice of antibiotic is usually reviewed once results from the microbiological test are available. Based on the test results, the antibiotic for UTIs when pregnant may also be changed to select the best antibiotic according to the specific bacteria causing the infection.

Antibiotics For UTI When Pregnant: First Choice Treatment

1. Nitrofurantoin

UTI tablets

Nitrofurantoin is recommended as the first-line antibiotic for UTI when pregnant.

Nitrofurantoin is usually prescribed in modified-release capsules (each capsule contains 100mg of nitrofurantoin), taken twice a day for 7 days.

Nitrofurantoin can be prescribed if other forms, for example, tablets, usually at a different dose (the frequency and number of pills taken). Check for the prescriber’s instructions on the recommended dose and the duration of the treatment.

Product information for nitrofurantoin confirms the long-term usage of this antibiotic since 1952 and its suitability as a treatment choice in pregnancy as well documented (eMC, 2020). Nitrofurantoin should be avoided at term in the pregnancy, during labour, and during delivery of the baby.

Nitrofurantoin For UTI In Pregnancy: Common Side Effects

Nitrofurantoin is generally well tolerated; however, as with many other drugs, there is a possibility of side effects. Possible side effects associated with nitrofurantoin treatment (frequency not known):

  • Upset stomach (abdominal pain, diarrhoea, nausea)
  • Yellow or brown discolouration of urine (this is not harmful)

Antibiotics For UTI When Pregnant: Second Choice Treatment


Second choice antibiotics for UTIs in pregnancy are used when no improvement in UTI symptoms is achieved after 48 hours of treatment or when the initial choice is not suitable, for example, due to urine culture test results.

1. Cefalexin:

Cefalexin is usually taken at 500mg twice daily for 7 days. Follow your prescriber’s instructions on the dosage and treatment.
Cefalexin comes in the form of capsules, tablets, and oral suspension. Cefalexin can be used in pregnancy, which is not known to be harmful (NICE, 2020).

Quick FAQ

How much water do I put in my cefalexin?
Add 64 mL of water to make up 100 mL. Close and shake well at once. Store the prepared suspension under refrigeration (2 to 8°C), and use it within 14 days of preparation. Shake well before use.

Cefalexin: Common Side Effects

Common side effects associated with cefalexin use may include:

  • Gastrointestinal side effects: diarrhoea, nausea (feeling sick)

 2. Amoxicillin:

Amoxicillin is recommended as a second-line treatment for UTI when pregnant only if bacterial test results confirm that this antibiotic is an effective treatment.

Amoxicillin is usually taken three times a day for 7 days. Follow the directions of your GP for dosage instructions and the duration of the treatment. Amoxicillin comes in the form of capsules and oral suspensions.

Quick FAQ

Can I take amoxicillin on an empty stomach?
You can take it with or without food. If it upsets your stomach, take it with food. Take your medicine at regular intervals. Do not take your medicine more often than directed.

Amoxicillin: Common Side Effects

Common side effects which can be experienced by patients taking amoxicillin may include:

  • Gastrointestinal side effects: diarrhoea, nausea (feeling sick)

Other Advice For Management Of UTIs When Pregnant

Pregnant patients with UTIs should maintain a good intake of fluids to avoid dehydration.
Pregnant women should seek urgent medical review if symptoms get worse at any time or when the condition fails to improve 48 hours after starting antibiotics (NICE, 2019).

Treatment Of Asymptomatic Bacteriuria When Pregnant

Asymptomatic bacteriuria (ASB) is a common condition during pregnancy. As the name suggests, this condition is characterised by the presence of bacteria in the urine without the symptoms of lower UTI (cystitis) or upper tract infection.

It is estimated that asymptomatic bacteriuria affects between 2% to 10% of pregnancies (Glaser & Schaeffer, 2015). When left untreated, ASB can lead to the development of acute pyelonephritis in pregnancy (sudden kidney infection), which can cause preterm birth and low birth weight (Smaill & Vazquez, 2015).

Routine screening for ASB early in pregnancy is recommended. All pregnant women should be screened for asymptomatic bacteriuria during their 1st antenatal appointment. A sample of urine is sent to check for the presence of bacterial infection.

What is the treatment recommendation for asymptomatic bacteriuria in pregnancy?

The recommendation for treatment of ABS in pregnancy follows the same choice of antibiotic selection as the management of UTIs discussed in earlier paragraphs. The primary antibiotics used include:

  • Nitrofurantoin
  • Amoxicillin (when urine test confirms suitability)
  • Cefalexin

Antibiotics Not Allowed For UTI When Pregnant

Trimethoprim used to be a first-line treatment in the management of UTIs in non-pregnant women. Pregnant women should not take trimethoprim.

Pain Relief Associated With UTI In Pregnancy

hot water for pain

Pregnant patients have minimal choice when it comes to the management of pain.

NICE guidelines recommend simple analgesia such as paracetamol to relieve UTIs in pregnancy (NICE, 2019).
The use of a hot water bottle may help manage pain.

Placing a hot water bottle on the stomach, back, or between thighs may elevate the pain.

OTC Products For UTI In Pregnancy:

Over-the-counter products containing sodium or potassium citrate are available to relieve symptoms of cystitis, a common form of UTI. Over-the-counter products reduce the acidity of the urine, which helps to reduce pain and burning sensation when urinating, a common symptom of cystitis and UTI.

Popular over-the-counter products include CanesOasis (sodium citrate) and Cystopurin (potassium citrate). Both products are not recommended for the management of UTI symptoms in pregnancy. Advice is to see a doctor before any products are used when pregnant.

Quick FAQ

Does cephalexin cause you to fall asleep?
Cephalexin oral capsules do not make you sleepy. Other adverse effects, however, may occur.
Is amoxicillin effective against tooth infections?
When it comes to treating tooth infections, amoxicillin is typically the first choice.