Chorioamnionitis and Endometritis
/Today we dive into intraamniotic infection (IAI), more commonly known as chorioamnionitis or endometritis. CO 712 reviews a lot of the surprisingly limited evidence on the management of IAI, and the essentials you need to know for your labor floor and for CREOGs.
IAI is an important topic because of its morbidity. 2-5% of term deliveries are complicated by chorioamnionitis. It is associated with acute neonatal morbidity, including things such as pneumonia, meningitis, sepsis, and death. Treatment intrapartum is associated with an over 10-fold decrease in GBS-neonatal sepsis. Maternal morbidities include dysfunctional labor curves that lead to further intervention, increased risk of postpartum hemorrhage due to atony, and peritonitis, sepsis, ARDS, and rarely death.
Risk factors for IAI include a longer length of labor and longer length of ROM. Additionally, it is thought that multiple digital vaginal exams in the setting of ROM can increase risk. Other, less obvious risk factors include cervical insufficiency, nulliparity, meconium-stained fluid, use of internal fetal or uterine contraction monitoring, presence of genital tract pathogens (ie. STIs, GBS, BV), alcohol and tobacco use, and of course previous history of chorioamnionitis.
The gold standard diagnosis is made off of a gram stain or culture of amniotic fluid, but this is obviously problematic! So in reality, there are three categories of IAI or IAI-risk that help guide clinicians into deciding therapy:
Isolated Maternal Fever: Single oral temperature of 39 C or greater OR an oral temperature of 38-38.9 C that persists when the temp is repeated after 30 minutes.
Suspected intraamniotic infection: Based on clinical criteria, which includes maternal fever PLUS one of maternal leukocytosis, fetal tachycardia, or purulent or malodorous amniotic fluid.
Confirmed intraamniotic infection: Based on the gold standard of culture/gram stain.
Does every fever intrapartum need to be treated?
There are lots of things that can cause fever intrapartum or immediately postpartum other than chorioamnionitis, such as:
Misoprostol use and other types of drug fevers.
Epidural use.
Other sources of infection (ie. UTI, respiratory infection).
Also… being in a hot room (girl, labor is hard work)!
For isolated maternal fever of 38-38.9, CO 712 states that without other clinical criteria indicating infection and with/without persistent temperature elevation:
Few data exist to guide appropriate management of women with isolated intrapartum fever in absence of other clinical signs suggesting intra-amniotic infection.
Consider antibiotics, but should definitely still communicate to pediatric team.
Our tendency is to treat persistent temperatures in this range in most cases.
Antibiotic Therapy: from CO 712:
ACOG CO 712
Once postpartum, antibiotics should not need to continue based on principle. Instead, antimicrobial therapy should be based on risk factors for postpartum endometritis:
Women who deliver vaginally may NOT require antibiotics postpartum as they are less likely to develop endometritis.
However, give an additional dose if bacteremia or persistent fever are present.
Women undergoing cesarean deliveries should receive at least one additional dose of antimicrobial agents after delivery is recommended.
One additional dose of chosen regimen + clindamycin 900 mg IV or metronidazole 500 mg IV.
Postpartum endometritis occurs when infection is not totally cleared out after delivery and affects the endometrium. Risk factors include chorioamnionitis, cesarean delivery, prolonged labor or ROM, manual placental removal, and all the chorioamnionitis risk factors above.
The diagnosis is based on the presence of postpartum fever, along with tachycardia, uterine tenderness, foul smelling lochia, and/or leukocytosis.
Treating endometritis occurs most commonly with clindamycin and gentamicin, with the addition of ampicillin (“triple therapy”) for GBS-positive patients. The patient should be treated until 24-48 hours afebrile. Additional oral antibiotic therapy after successful IV therapy is not required as RCTs have demonstrated no improved outcomes. And of course if someone isn’t looking better, consider source control measures (i.e., D&C for retained POCs) or a different source of infection.