Chorioamnionitis

DEFINITION
Infection of the chorion, amnion and amniotic fluid typically due to ascending infection by organisms from normal
vaginal flora. Most often associated with prolonged labour. AETIOLOGY /EPIDEMIOLOGY
Incidence 1-5% of term pregnancies and up to **25% in preterm deliveries
• Most commonly results from organisms ascending from vagina
• May also result from haematogenous spread
• Predominant microorganisms include GBS, Bacteroides and Prevotella species, E. coli and anaerobic Streptococcus

Medscape: GBS infections are no longer the major cause of EOS. Gram-negative bacteria are now most
 predominant particularly Escherichia coli


RISK FACTORS
***Labour-related:
• **Prolonged ROM
• Preterm labour
• Long labour
• Multiple vaginal exams during labour - risk of developing chorioamnionitis increases with each vaginal examination
that is performed in the final month of pregnancy, including during labor
• Internal monitoring (Eg. fetal scalp electrode!)

**Infections:
• Bacterial vaginosis and other vaginal infections – *BV is also associated with preterm labour
• UTI in pregnancy

CLINICAL FEATURES
***Pay attention to these if you get a patient in the OSCE with fever esp. immediately post delivery!! REMEMBER to ask about FOUL/PURULENT cervical discharge/lochia!!
• (Temperature, Tachycardia, Tenderness, Foul discharge)
These are CLASSIC features!!! – therefore must know all:
1. Maternal fever - (intrapartum temperature >100.4°F or >37.8°C) à Most frequently observed sign
2. Maternal tachycardia
3. Fetal tachycardia
4. Uterine tenderness
5. Foul and purulent cervical discharge or lochia* [See end of notes]
6. [Along with maternal leukocytosis]
• **NB: Some patients ASYMPTOMATIC – “Silent chorioamnionitis”!! –
• Other pts may also be hypotensive, diaphoretic, cold + clammy (Septic shock)
• Fetus may have non-specific signs of sepsis (EOS = Early onset sepsis) – assc with WCC and CRP

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