Urine Infection When You are Pregnant

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Understanding the urinary tract

There are two kidneys, one on each side of the abdomen. They make urine which drains down the ureters into the bladder. Urine is stored in the bladder and is passed out through the urethra from time to time when we go to the toilet.

What is a urine infection and what are the symptoms?

A urine infection is caused by bacteria (germs) that get into your urine. This may cause:

• Asymptomatic bacteriuria. This is where bacteria are found in your urine, but are not causing any symptoms.
• Cystitis (bladder infection). This is common in both pregnant and non-pregnant women. Typical symptoms are pain when you pass urine, and passing urine frequently. You may also have other symptoms such as pain in your lower abdomen, blood in your urine, and fever (high temperature).
• Kidney infection. This is uncommon, but may occur as a complication from cystitis or asymptomatic bacteriuria. Symptoms may include: pain in a loin (side of the abdomen over your kidney), fever, feeling sick (nausea), vomiting and/or diarrhoea, and blood in your urine. You may also have symptoms of cystitis. Not all the symptoms may develop, and sometimes a kidney infection can just cause vague symptoms such as feeling generally unwell.

What causes a urine infection?

Most urine infections are caused by bacteria that come from your own bowel. They cause no harm in your bowel but can cause infection if they get into other parts of your body. Some bacteria lie around your anus (back passage) after you pass a stool (faeces). These bacteria can sometimes travel to your urethra and into your bladder. Some bacteria thrive in urine and multiply quickly to cause infection.

Women are more prone to urine infections than men as their urethra (the tube from the bladder that passes out urine) is shorter and opens nearer the anus. In addition, pregnant women are more prone to urine infections than non-pregnant women. This is probably due to the hormone changes of pregnancy that affect the urinary tract and tend to slow down the flow of urine.

What is the risk of a urine infection when you are pregnant?

If you have a kidney infection when you are pregnant, it may cause problems such as early labour and/or a small baby. (This is in addition to you being unwell with the infection.) A kidney infection is uncommon but may develop as a complication from cystitis, or from a urine infection with no symptoms at first (asymptomatic bacteriuria).

Urine checks during pregnancy

• You should have a routine urine test early in pregnancy. Treatment is advised if any bacteria are found - even if you have no symptoms (asymptomatic bacteriuria). Also, if bacteria are found, you should have regular routine urine tests throughout the pregnancy.
• You should also have a urine test if you develop symptoms of cystitis or kidney infection at any stage during pregnancy.

What is the treatment of a urine infection when you are pregnant?

• A short course of antibiotics is the usual treatment. Any symptoms will usually improve within a few days. See a doctor if symptoms have not gone, or nearly gone, after a few days. (Some bacteria are resistant to some antibiotics. This will be identified from the urine sample. A change of antibiotic is needed in some cases if the bacterium is found to be resistant to the first antibiotic.)
  Note: this is a little different to the treatment of cystitis in non-pregnant women. Not having any treatment is an option in non-pregnant women as cystitis often goes without treatment. However, if you are pregnant, antibiotics are usually advised.
• Paracetamol will usually ease any pain, discomfort, or fever (high temperature).
• Have lots to drink is traditional advice to 'flush out the bladder'. However, there is no proof that this is helpful when you have cystitis. Some doctors feel that it does not help, and drinking lots may just cause more (painful) toilet trips. Therefore, it is difficult to give confident advice on whether to drink lots, or just to drink normally, when you have symptoms.
  However, when you do not have symptoms, it may help to drink lots to 'flush out the bladder frequently' as this may help to prevent urine infections.

It is usual to do a repeat urine test after the course of treatment to check that your urine is clear of bacteria.

© EMIS and PIP 2006   Updated: June 2006   PRODIGY Validated

The authors and editors of this article are employed to create accurate and up to date content reflecting reliable research evidence, guidance and best clinical practice. They are free from any commercial conflicts of interest. Find out more about updating.

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