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 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 more often. 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 your loin (side of the abdomen over your kidney), fever, feeling sick, vomiting and/or diarrhoea, and blood in your urine. You may also have symptoms of cystitis. Not all the symptoms may develop. 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. Pregnant women are also more prone to urine infections than non-pregnant women. This is partly due to the hormonal changes of pregnancy that affect the urinary tract and tend to slow down the flow of urine.

Can a urine infection affect my pregnancy?

If you have a kidney infection when you are pregnant, you can feel very unwell. But it may also cause problems such as early labour and/or a small baby. A kidney infection is uncommon but may develop as a complication from cystitis or from a urine infection. There may be no symptoms at first (asymptomatic bacteriuria).

Urine checks during pregnancy

• You should usually have your urine tested early in pregnancy. Your midwife may ask you to bring a sample in a container or sample bottle. Treatment is advised if any bacteria are found - even if you have no symptoms. If bacteria are found, you should have regular routine urine tests throughout the pregnancy.
• You should also have your urine tested 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?

Antibiotics

There are several different types of antibiotic that can help. Your doctor will choose the type most likely to help you. A seven-day course of an antibiotic is the usual treatment if you have symptoms. A three-day course may be given if you have no symptoms but bacteria are found in your urine. Any symptoms will usually improve within a few days. However, it is very important that you complete the course of antibiotics. The antibiotic used to treat urine infections in pregnant women are safe to take in pregnancy. They will not harm your baby.

You should see a doctor if your symptoms do not go, or if you feel worse after a few days. Some bacteria are resistant to some antibiotics. This can be identified from tests done on the urine sample. A change of antibiotic is needed 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, treatment with an antibiotic is usually advised.

Painkillers

Paracetamol will usually ease any pain, discomfort, or fever.

Drinking fluids

If you have cystitis then having plenty 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 mild symptoms of cystitis. However, if you have a fever and/or feel unwell, having plenty to drink helps to prevent dehydration.

But, when you do not have symptoms, it may help to have plenty to drink to flush out the bladder frequently. It is thought that 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.

References

• Guidelines on Urological Infections, European Association of Urology (2011)
• Urinary tract infection (lower) - women, Prodigy (October 2009)
• Schnarr J, Smaill F; Asymptomatic bacteriuria and symptomatic urinary tract infections in pregnancy. Eur J Clin Invest. 2008 Oct;38 Suppl 2:50-7. [abstract]
• Vazquez JC, Villar J; Treatments for symptomatic urinary tract infections during pregnancy. Cochrane Database Syst Rev. 2003;(4):CD002256. [abstract]