Intrauterine infection (chorioamnionitis)

Intrauterine infection, also known as chorioamnionitis, is infection within the womb.

Intrauterine infection is infection within the womb, which, in the context of pregnancy, usually means infection of:

  • the membranes that surround the baby
  • the umbilical cord
  • and/or the amniotic fluid.

Research suggests that intrauterine infection may be responsible for as many as 40 percent of preterm births, with higher rates in earlier gestations (very premature babies). 

What is intrauterine infection?

The womb, amniotic fluid and the environment in which the baby develops can become infected with bacteria. These are usually natural bacteria that many women carry in the vagina or skin, which are harmless normally, but have migrated to parts of the body where they shouldn't be. The most common cause of intrauterine infection is through the vagina and cervix, but it can also come through the placenta, through the fallopian tubes or via invasive procedures such as amniocentesis.

Infections that could ascend to the womb include E-Coli and Group B Streptococcus (GBS), bacterial vaginosis, chlamydia, trichomona, gonorrhoea, syphilis and HIV.

If the infection reaches the womb it can cause the fetal membranes (membrane of the sac that surrounds a baby in the womb, also called amnion or chorion) to become inflamed and infected. This is called chorioamnionitis. If the umbilical cord is affected it is called funisitis.

What are the effects of chorioamnionitis?

This is an infection of the membranes of the sac that holds a baby and the waters, and usually occurs when an undetected infection progresses up into the womb from the vagina. The infection causes the membranes to become inflamed and this may in itself trigger preterm contractions. It could also cause the waters to break early (also known as preterm premature rupture of the membranes, or PPROM for short). The baby may need to be born soon to prevent a more serious infection.

Look out for these symptoms of chorioamnionitis:

  • high temperature
  • a foul-smelling vaginal discharge
  • fast pulse rate
  • pain in your abdomen.

If you have any of these symptoms, seek advice from your healthcare team as soon as possible as you may need treatment.

Urinary tract infections (UTIs)

Often caused by the E-Coli bug, UTIs affect about five percent of pregnant women. In between one third and a half of those women, the UTI will travel up into the kidneys, causing acute pyelonephritis, a kidney infection that can cause premature labour and low birthweight. Watch out for these symptoms of UTIs:

  • high fever
  • nausea
  • vomiting
  • pain in your sides or lower back
  • discomfort or pain when passing urine
  • blood in the urine

If you have any of these symptoms, contact your healthcare team as soon as possible as you may need antibiotics.

Treatment for infections

It is not always easy to spot an infection; in the early stages there may be no obvious symptoms. If there is any indication of an infection, for example if you are running a fever, your healthcare team will test you with either a blood test or a simple swab.

If your waters break early (PPROM), you may be given antibiotic tablets as a matter of course, to reduce the risk of chorioamnionitis.

If the infection has progressed beyond a certain point, or if you are very unwell you may need to be admitted to hospital for intravenous antibiotics and in some cases the baby may need to be delivered. In most cases of PPROM, taking antibiotics helps to reduce the likelihood of chorioamnionitis, reduces the number of births happening within 48 hours of waters breaking, and reduces the chances of the baby developing an infection.

Read more about waters breaking early/preterm premature rupture of the membranes (PPROM)


J David, Steer P et al (2010) High risk pregnancy, management options, Elsevier Saunders

Acute chorioamnionitis and funisitis: definition, pathologic features, and clinical significance
Kim, Chong Jai et al. American Journal of Obstetrics & Gynecology , Volume 213 , Issue 4 , S29 - S52

BMJ Best Practice (accessed Oct 2016)

Sangkomkamhang US, Lumbiganon P, Prasertcharoensook W, Laopaiboon M (2009)Antenatal lower genital tract infection screening and treatment programs for preventing preterm delivery, The Cochrane Collaboration, Wiley

RCOG (2011) When your waters break early (preterm prelabour rupture of membranes) – information for you, Royal College of Obstetricians

RCOG (2006) Preterm Prelabour Rupture of Membranes, Green top guideline No 44.

Rennie JM (2012), Rennie and Robertons Textbook of Neonatology, Fifth edition. Elsevier.

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    Last reviewed on October 4th, 2016. Next review date October 4th, 2019.

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    Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.
    • By Wynneh (not verified) on 6 Mar 2020 - 06:27

      Hey my water broke at 17w and my doctor send me home and put me on restrictions but without antibiotics. Says nothing can be done just have to wait and observe. Is this advisable

    • By Kat (not verified) on 15 Apr 2020 - 14:33

      Hey Wynneh,
      I'm going through the same thing for my water broke last week at 17 weeks and I received no antibiotics. I really dont understand why some Dr. do and some dont? How are things going in your situation?

    • By Cindy (not verified) on 29 Dec 2019 - 07:52

      Hi my water broke on the 15th June then I rushed to hospital and the liquid was still coming though even when im there at hospital then contractions started. On the 17th they sent me home but returned to hospital same day evening. I started to bleed around 1:00am om the 18th then transfared for c section the baby almost didn't make it had some problems but became OK eventually but I lost my uterus few days later I'm wondering what could have gone wrong

    • By Hailey (not verified) on 9 Dec 2019 - 01:42

      Hello. I lost my daughter at 20 weeks gestation due to PPROM. My doctor believes it was because of an undetected infection. I am hoping to get pregnant again very soon and my doctor wants to start me on antibiotics as soon as I get a positive pregnancy test. My concern is, will the antibiotics affect my next baby in a significant way?

    • By blessing (not verified) on 1 Aug 2019 - 12:36

      I was tested and nurse said am pregnant now I went for scan and scan said he couldn't find the sac of the baby and am also having pid.
      please does pid grows like a pregnancy bump?
      he said it's positive in the screen.

      talk to me please.

    • By Sarah (not verified) on 21 May 2019 - 03:44

      Hi my first IVF I lost to prem labour at 22weeks no one tested me for StepB the infection traveled up to my uterus and my cervix opened. Emergency sutra was not successful..I am now 16 weeks pregnant and I have same symptoms my Consultant won’t give antibiotics unless they detect StepB in urine.. my swabs show StepB I am in severe pain. Burning and pressure in vagina. Regular trips to toilet. I am scared of history repeating please help. Every swan shows sensitivity to different antibiotics why won’t my Consultant keep me on antibiotics throughout pregnancy? What should I do

    • By Chelsea (not verified) on 16 May 2019 - 20:31

      I have just found out I'm pregnant and also just received my results from a scan I had before my pissitive test. I have a large absess in a fallopian tube and now I'm worried I'm not going to be able to carry this pregnancy or will it affect my baby?

    • By Caroline (not verified) on 28 Mar 2019 - 12:13

      I have been draining slowly only at night, I don't know if it is urine or amniotic fluid . Am 27 weeks pregnant. How do I know the difference

    • By Midwife @Tommys on 15 Apr 2019 - 15:10

      For most women, if their waters have broken, they would leak constantly, particularly if they are upright and walking around. However, if you are worried that your waters have gone it is important to seek advice from your midwife or hospital team.

    • By kesavan (not verified) on 8 Jul 2019 - 08:08

      pls consult with your doctor as soon as possible

    • By Boitumelo (not verified) on 19 Mar 2019 - 20:25

      Hi I have a pain when am passing urine but this pain also continue even when am not passing urine

    • By Ghazala (not verified) on 18 Mar 2019 - 15:49

      Hi . My waters broke at 18w and am 21w3d now , is there any possibility of creeping infection without any symptoms ??

    • By Courtney (not verified) on 27 Jul 2019 - 01:18

      Hi, I am going through the same situation. I have been leaking since 17 weeks And now am 20 weeks 4 days. I am concerned that I am going to lose my baby. Hoping you had a good outcome, looking for hope.

    • By Concilia (not verified) on 4 Sep 2019 - 17:52

      How did it go I'm in the same situation

    • By Nwando (not verified) on 26 Feb 2019 - 20:20

      I usually feel pain when passing urine especially during my ovulation and prior to me seeing my period.the pain comes as am passing the urine but disappears gradually after some time . I have done UTI but nothing was found.pls what can I do

    • By Midwife @Tommys on 27 Feb 2019 - 12:27

      Hi Nwando
      If you have had your urine checked and you do not have a UTI, then please go back to your Doctor. They may need to refer you for a Gynaecology review to make sure that your bladder and kidneys are ok. Please take care, all the best, Tommy's Midwife

    • By Emma (not verified) on 13 Feb 2019 - 15:12

      My waters broke at 26 weeks. I'm currently now 29 weeks I received the essential steroid injections and antibiotics. But for the past few days I've felt feverish but temp hasnt been high :/ and my abdamon is really sore.

    • By Midwife @Tommys on 15 Feb 2019 - 15:17

      Dear Emma,
      I would strongly advise for you to ring the maternity unit to be reviewed if you are feeling feverish and having pain.
      Best wishes
      Tommy's midwife

    • By Gia (not verified) on 19 Nov 2018 - 02:49

      Hi. My first son was born with an IUGR diagnosis. I see that an uterine infection could have been a cause. My second pregnancy was lost early due to acute deciduitis and now I'm hoping to get pregnant again. Would I need to regularly check for infections during the pregnancy or do anything special ahead of time? Are there intervals at which this should be checked for? I had no symptoms the second pregnancy but did have a tooth infection the first that I wonder if it was the cause.

    • By Shannon (not verified) on 19 Sep 2018 - 10:13

      Hi I wonder if u can help me my baby isn't growing properly . She is 29 weeks formed but is below the growth chart everyone I am measured once at hospItal and once by tape measure she drops.

    • By Midwife @Tommys on 21 Sep 2018 - 11:17

      Hi Shannon, If your baby is below the expected growth, your midwife will refer you for a scan. Measurement by tape measure is only a guide but if the measurement is 3 or more cm below the number of weeks, you will be referred. If you are concerned please talk to your midwife. Best wishes

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