Chorioamnionitis
•Bacterial infection of the fetal amnion and chorion
membranes that is a peripartum complication and may lead
to early onset sepsis of the child and mother.
Epidemiology
• Thought 1-4% of all births in the US
• 40-70% of preterm births with PPROM or spontaneous labor
• Occurrence declines as pregnancy advances toward term gestation.
• Failure to progress and advancement to C section also increases the risk with
12% of C section births being complicated by this as well.
• More common in young black women than white, and more common in baby
boys that are PPROM than baby girls of the same condition
Origin of infection
• Abnormal bacterial colonization of the distal colon during pregnancy may create an abnormal vaginal
and cervical microbial environment.
• Studies have demonstrated that other types of bacteria residing in the vagina, cervix, or both ascend
through intact or ruptured fetal membranes and initiate amniotic fluid infection, chorioamnionitis, or
both. [25]
• Urinary tract infection during pregnancy can bathe the vagina with bacterial pathogens and is a
recognized risk factor for neonatal sepsis. This observation is particularly true for untreated
asymptomatic GBS-related bacteriuria. A high maternal body mass index increases the risk of EOS
caused by GBS.
• Bacterial vaginosis is associated with premature labor, although overt infection of the neonate with
microbes causing bacterial vaginosis is uncommon
• For example, periodontitis is linked to prematurity, low birth weight, and fetal growth restriction. [30]
• Blood types A and O are also associated with an increased risk for chorioamnionitis.
• In the mid trimester of pregnancy, ultrasonographic evidence of a short cervix may be the only clinical
finding in intraamniotic fluid infection.
Bugs
• Mostly polymicrobial
• When cultured, most commonly genital mycoplasmas
• Ureaplasma urelyticum
• Mycoplasma hominis
• Less common:
•
•
•
•
Gardenella vaginalis
Basteroides
GBS
Ecoli
Risks
• Clinical events associated with chorioamnionitis include the following:
•
•
•
•
•
•
•
•
•
History of premature birth (with increasing risk at earlier gestational age)
Premature labor
Prolonged rupture of the fetal membranes
Nulliparity
Teen aged
African American
Multiple/Intrapartum vaginal exams
GBS positive
STD and genital infections
Sx and Signs
• Fever (an intrapartum temperature >100.4ºF or >37.8ºC)
• Significant maternal tachycardia (>120 beats per minute [bpm])
• Fetal tachycardia (>160-180 bpm)
• Purulent or foul-smelling amniotic fluid or vaginal discharge
• Uterine tenderness
• Maternal leukocytosis (total blood leukocyte count >15,000-18,000
cells/μL)
• The fetus may also have tachycardia (>160-180 bpm). Although heart rate characteristics used to
diagnose EOS are under investigation, [113] this type of analysis has not been applied to the fetal
heart rate when chorioamnionitis is evident. A biophysical profile (BPP) performed on the fetus using
ultrasonography may reveal a lower than normal score, but ultrasonic biophysical profile assessment
has not been predictive of clinical chorioamnionitis. [114]
• Lack of fetal breathing has been associated with fetal infection. [115, 116] Intrauterine
ultrasonography has identified "sludge" at the amniotic fluid interface with the cervix that is also
associated with hyperechogenic, free-floating material in the amniotic fluid. [7] This finding was seen in
asymptomatic women at risk for preterm delivery. More recent studies confirm that amniotic fluid
sludge is a useful marker of microbial invasion of the amniotic cavity (MIAC), histologic
chorioamnionitis, and finisitis—conditions that increase the risk for preterm delivery at an extreme
gestational age. [117] Aseptic aspiration of the "sludge" showed the material had a low glucose
content, many neutrophils, and gram-positive cocci. Furthermore, electronic fetal monitoring lacks
precision to identify the fetal inflammatory response syndrome and subsequent neonatal sepsis. [118]
Ddx
• Cervicitis
• UTI/Cystitis in mother or child
• Pediatric Herpes Simplex Virus Infection
• Appendicitis
• Pyelonephritis
• Epidural anesthesia
• Placental Abruption
Work up
• Subclinical Dx
• CBC
• CRP
• Amniocentesis and culture
• BPP to eval baby
• While good to be cautious, beware of the practice of “defensive
medicine” and overtreating.
References


Medscape:
http://emedicine.medscape.com/article/973237-overview
 "Chorioamnionitis and PROM" Drs. A. Rahman, S. Hatem
 https://www.slideshare.net/mobile/100001377961715/chorioamn
ionitis-and-prom-nahrain-university