What Is Chorioamnionitis?

Medically Reviewed by Nivin Todd, MD on April 29, 2023
4 min read

‌Chorioamnionitis, sometimes called intra-amniotic infection and inflammation, is a serious bacterial infection that can affect pregnant women. Women can develop this condition before their water breaks or after they go into labor.

This infection can affect any of the tissues surrounding the fetus, including the following:‌

  • Placenta
  • ‌Chorion (outer membrane)
  • ‌Amnion (inner membrane)
  • ‌Amniotic fluid

‌The medical condition affects about 1% to 5% of full-term births, but it can affect 40% to 70% of pre-term births. It is often the main reason for premature delivery. Chorioamnionitis can lead to serious infections in both the mother and baby if left untreated.

‌Chorioamnionitis is caused by bacteria. Usually, these bacteria are from different species, so they’re called poly-microbial bacteria. They can be bacteria common to your urinary or gastrointestinal tract, or they can be from an outside source. 

‌Common types of bacteria that cause chorioamnionitis include the following:‌

  • E. coli
  • ‌Group B streptococci (GBS)
  • ‌Ureaplasma
  • Mycoplasma hominis

‌The infection can start in the vagina or anus and spread into the uterus. It can also begin in the uterus if a tear or other rupture allows bacteria to spread there.

‌‌Not all women are at risk of chorioamnionitis. Your age, physical wellbeing, and lifestyle or health conditions could increase your risk of developing it.

‌Reasons that increase your chances of developing chorioamnionitis are as follows:‌

  • Your water breaks prematurely.
  • You have a very long labor before delivery.
  • You get a lot of vaginal exams during labor.
  • You have a sexually transmitted infection
  • You have a separate vaginal, urinary, or placental infection.
  • You’re having your first child.
  • You’re having another child and you experienced chorioamnionitis during your first pregnancy.
  • You get epidural anesthesia during labor. 
  • You have a short cervix.
  • You use drugs, tobacco, or alcohol.
  • You get internal fetal monitoring during labor.
  • You are immune-compromised.‌

‌Sometimes women don’t display symptoms of chorioamnionitis, especially if they develop it earlier in their pregnancy. In a majority of cases, the most common symptom is a persistent fever above 100.4 degrees Fahrenheit.

Other signs and symptoms may include the following:‌

  • Rapid heartbeat (above 100 beats per minute)
  • ‌Fetal rapid heartbeat (above 160 beats per minute)
  • ‌Tender uterus
  • Sweating
  • ‌Bad smelling fluid discharge

‌Only a doctor can properly diagnose this serious condition. The most common way to diagnose chorioamnionitis is through a physical evaluation to check for the signs and symptoms. 

Your doctor may order blood culture and urine tests as well. These tests check for the presence of bacteria in your body. A complete blood count (CBC) test checks your white blood cell count and other markers.‌‌

Along with these tests, your doctor may order a GBS vaginal culture, an ultrasound, and a sample of your amniotic fluid. Usually, the amniotic fluid sample can only be taken if your water has already broken.

‌As chorioamnionitis is a serious infection, it needs immediate treatment. Antibiotics are the most common treatment to keep the infection under control. They’re given in the vein and are known as intravenous antibiotics. You may also receive acetaminophen to reduce your body temperature.

You’ll need to keep taking antibiotics until the infection has cleared. If you develop the infection during labor, you must continue to take antibiotics until after the baby is born.

If your baby has picked up the infection and their condition isn’t stable, your doctor may suggest that you induce labor. Once your baby is born, they’ll also receive direct IV antibiotics.

‌There are numerous potential complications of chorioamnionitis for the mother and baby.

You may develop the following complications:‌

  • Bleeding after delivery
  • ‌Blood clots in the leg
  • ‌Pelvic sores
  • ‌Endometritis
  • Sepsis

‌In serious cases, you may develop these complications:‌

  • Septic shock
  • ‌Small clots throughout the bloodstream
  • ‌Shortness of breath with skin turning blue

‌Your baby may develop the following short-term or long-term complications:‌

  • Sepsis
  • ‌Meningitis
  • Pneumonia
  • ‌Seizures
  • ‌Cerebral palsy
  • ‌Impaired brain function
  • ‌Lung disease

‌‌If the infection is widespread long before your doctor diagnoses it, your pregnancy may result in stillbirth or death after delivery.

‌‌Sometimes, you can prevent chorioamnionitis. Other times, you may develop this infection regardless of preventive measures. 

Routine checkups may identify vaginal inflammation or early signs of infection. During your last month of pregnancy, your doctor may also order blood tests that check for GBS — common bacteria that cause chorioamnionitis. 

During labor, your chances of developing the infection lower when you have fewer vaginal exams and don’t use internal fetal monitoring.

If you display any of the above signs and symptoms, reach out to your doctor to schedule a visit. Regular checkups could help you enjoy a healthy, complication-free pregnancy and delivery.