Chorioamnionitis, often called “chorio,” is a bacterial infection that occurs during pregnancy. The condition affects the membranes surrounding the fetus, known as the chorion and amnion, as well as the amniotic fluid. The name reflects this: “chorion” and “amnion” refer to these protective membranes, while “-itis” signifies inflammation. This infection can arise before or during labor and, while serious, can be managed effectively with prompt intervention.
Causes and Risk Factors of Chorioamnionitis
The cause of chorioamnionitis is a bacterial infection. Bacteria normally present in the vagina or rectum, such as E. coli and Group B streptococci, ascend into the uterus. Once the amniotic sac has ruptured, the pathway for these bacteria to travel upwards is more accessible.
A primary risk factor is the premature or prolonged rupture of membranes, which is when the “water breaks” well before labor begins or for an extended period before delivery. A long labor process can also elevate the risk.
Other factors that can contribute to the development of chorioamnionitis include multiple vaginal examinations after the membranes have ruptured. Pre-existing infections in the mother, such as bacterial vaginosis, can also increase susceptibility. The use of internal fetal or uterine monitoring devices is another recognized risk factor.
Recognizing the Signs
The signs of chorioamnionitis can vary, but medical staff look for several indicators in the mother. A maternal fever is one of the most common symptoms, often accompanied by a rapid heart rate (maternal tachycardia). Tenderness or pain in the uterus upon physical examination is another significant sign.
Another symptom is a change in the vaginal discharge or amniotic fluid, which may become discolored or develop a foul smell. Some women may also experience sweating. Not all women with the condition will show obvious symptoms, which makes regular monitoring during labor important.
For the fetus, the primary sign is fetal tachycardia, a sustained heart rate above the normal range. Healthcare providers monitor the fetal heart rate closely during labor, and a persistent elevation can be an early indicator of the condition, prompting further investigation.
Diagnosis and Medical Intervention
Chorioamnionitis is diagnosed based on a clinical assessment of the mother’s symptoms. The presence of a maternal fever combined with other signs, like uterine tenderness or a rapid heart rate, often leads to a diagnosis. Healthcare providers may use blood tests to support their findings, as these can show an elevated white blood cell count, a general indicator of infection.
In some situations, a procedure called amniocentesis might be considered. This involves taking a small sample of amniotic fluid with a needle to test it directly for bacteria, though this is not a routine test for diagnosis.
Once a diagnosis is made, treatment begins immediately to prevent complications. The standard approach involves administering broad-spectrum intravenous (IV) antibiotics, such as ampicillin and gentamicin, to fight the bacteria.
A primary part of treating chorioamnionitis is the delivery of the baby and the placenta. This step removes the source of the infection. If labor is not progressing, it will likely be induced to expedite the delivery. Antibiotics are continued after the baby is born to ensure the infection is fully resolved.
Potential Complications for Mother and Infant
Prompt treatment minimizes risks, but chorioamnionitis can lead to complications for both the mother and infant. For the mother, the infection can spread from the uterus into the bloodstream, a condition known as bacteremia or sepsis. There is also an increased risk of endometritis (an infection of the uterine lining after delivery), heavier bleeding after birth, and a higher likelihood of needing a Cesarean section.
For the infant, the risks are heightened if the baby is born preterm. The infection can be transmitted to the newborn, potentially leading to serious conditions like pneumonia or meningitis, an infection of the lining of the brain and spinal cord. Sepsis, a widespread infection in the bloodstream, is another concern for the baby. In some cases, chorioamnionitis has been linked to potential long-term neurodevelopmental issues.