Chorioamnionitis and Your Pregnancy

Pregnant woman at doctor

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Chorioamnionitis is a bacterial infection of the membranes that surround the fetus in the uterus (the chorion and amnion) and the amniotic fluid (the liquid that the fetus floats in) during pregnancy. This condition occurs in approximately 2 percent of births, and when not detected and treated, can lead to serious complications for the mother and baby.

The consequences of chorioamnionitis are varied. In the best cases, when the infection is detected and treated in a timely manner, there may be no long-term complications for you or your baby lasting beyond delivery. Doctors will monitor your baby for signs of a resulting infection, but according to the March of Dimes, fortunately, about 95 percent of babies who are infected with group B strep, one of the bacteria strains found in chorioamnionitis, recover with help from antibiotics. Premature babies are more vulnerable to developing serious complications or dying due to infections.

Causes and Risk Factors

Chorioamnionitis occurs when bacteria breaches the normal defenses of the uterus, usually ascending from lower in the vagina. Common culprits include group B strep and E. coli. You are more likely to develop chorioamnionitis if you have a long delivery after your membranes have ruptured, also known as when your water breaks. Chorioamnionitis occurs most commonly in preterm births.


If the infection occurs during labor or delivery, signs of chorioamnionitis may include:

  • Fever
  • Sweating
  • Elevated fetal or maternal heart rate
  • Uterine pain
  • Abnormal amniotic fluid smell

If the infection occurs during pregnancy, you may not experience any symptoms.

Diagnosis and Treatment

If a doctor suspects you have chorioamnionitis before you go into labor, they can diagnose the infection via amniocentesis and by testing the amniotic fluid for signs of bacteria. If the condition is suspected during labor, your doctor may make a diagnosis and opt for treatment based on clinical symptoms.

How your doctor treats your infection depends on your individual circumstances. Usually, treatment involves intravenous antibiotics. Other cases require Immediate delivery of the baby. After delivery, both you and your child may need to continue taking antibiotics for a day or two.

If the condition is severe or isn't treated, you may face possible complications such as an abdominal or pelvic infection, sepsis (a blood infection), endometritis (an infection in the lining of the uterus), or blood clots in the lungs or pelvis. Complications for your child can include sepsis, respiratory problems, and meningitis (an infection of the brain and spinal cord). 

In some cases, especially when chorioamnionitis occurs earlier in pregnancy and is asymptomatic, the infection may cause premature labor or even stillbirth. Research suggests that chorioamnionitis is a common factor in unexplained stillbirths, and there is some evidence that the condition itself might be the cause of the stillbirth in these cases. Unfortunately, not much is known at this point about who might be at risk for early asymptomatic infections or how to best diagnose and treat early infections.

7 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cleveland Clinic. Chorioamnionitis.

  2. March of Dimes. Group B Strep Infection.

  3. Cedars Sinai. Chorioamnionitis.

  4. Stanford Children’s Health. Chorioamnionitis.

  5. Tita AT, Andrews WW. Diagnosis and management of clinical chorioamnionitis. Clin Perinatol. 2010;37(2):339-54.  doi:10.1016/j.clp.2010.02.003

  6. Cleveland Clinic. Chorioamnionitis: management and treatment.

  7. Gordon A, Lahra M, Raynes-Greenow C, Jeffery H. Histological chorioamnionitis is increased at extremes of gestation in stillbirth: a population-based study. Infect Dis Obstet Gynecol. 2011;2011:456728. doi:10.1155/2011/456728

Additional Reading
  • Holzman, Claudia, Ximin Lin, Patricia Senagore and Hwan Chun. Histologic Chorioamnionitis and Preterm Delivery. American Journal of Epidemiology 2007 166(7):786-79.

  • Lahra MM, Gordon A, Jeffery HE. Chorioamnionitis and fetal response in stillbirth. Am J Obstet Gynecol. 2007 Mar;196(3):229.e1-4. doi: 10.1016/j.ajog.2006.10.900

  • Moyo SR, Hägerstrand I, Nyström L, Tswana SA, Blomberg J, Bergström S, Ljungh A. Stillbirths and intrauterine infection, histologic chorioamnionitis and microbiological findings. Int J Gynaecol Obstet. 1996 Aug;54(2):115-23. doi: 10.1016/0020-7292(96)02705-1

  • Tolockiene E, Morsing E, Holst E, Herbst A, Ljungh A, Svenningsen N, Hägerstrand I, Nyström L. Intrauterine infection may be a major cause of stillbirth in Sweden. Acta Obstet Gynecol Scand. 2001 Jun;80(6):511-8.

  • Chorioamnionitis. University of Virginia Health System. 
  • Group B Strep Infection. March of Dimes. 

By Krissi Danielsson
Krissi Danielsson, MD is a doctor of family medicine and an advocate for those who have experienced miscarriage.