Obstetrics

Chorioamnionitis

Suspected intra-amniotic infection is usually an ascending infection associated with ruptured membranes; it can cause maternal sepsis, fetal compromise and early-onset neonatal infection, so prompt senior assessment, antibiotics and a birth plan are required.

In a nutshell

Suspected intra-amniotic infection is usually an ascending infection associated with ruptured membranes. Suspect it from maternal fever or systemic illness with uterine tenderness, maternal or fetal tachycardia, purulent or offensive liquor or inflammatory change. Assess for maternal sepsis, give prompt antibiotics, involve senior obstetric and neonatal teams, and arrange the safest timely birth; infection alone is not an automatic indication for caesarean birth.

Classic presentation

A person with prolonged PPROM develops fever, uterine tenderness, maternal and fetal tachycardia and offensive liquor. Start the sepsis and intrapartum infection pathway, alert neonatology and make a birth plan without waiting for a single confirmatory test.

Key points

Use combined clinical assessment, maternal blood tests and fetal heart-rate assessment in PPROM; no single marker rules infection in or out.
Pregnancy and the first 6 weeks after birth are high-risk contexts for sepsis; do not rely on fever alone.
For suspected chorioamnionitis, NICE NG195 recommends prompt intrapartum antibiotics and continuing them until birth.
In PPROM, suspected infection is a contraindication to routine expectant management; arrange timely birth after maternal stabilisation.
Chorioamnionitis is not by itself an indication for caesarean birth; route depends on maternal and fetal condition and the likelihood of safe vaginal birth.
Tell neonatology and use NICE NG195 to assess the newborn for early-onset infection.

First-line investigation

Immediate maternal observations and fetal assessment, plus sepsis blood cultures, lactate and organ-function bloods when sepsis is suspected; in PPROM use the combined RCOG assessment rather than an isolated CRP, WBC or CTG.

Management

Assess for maternal sepsis

Move to acute maternity care, call a senior clinical decision maker, assess ABCDE and fetal status, take cultures and lactate when indicated, and start high-risk sepsis treatment without delay.²

Start intrapartum antibiotics

For suspected chorioamnionitis, begin the current NICE NG195 antibiotic regimen as soon as possible, checking allergy, renal function, local microbiology advice and drug-monitoring requirements; do not delay for cultures if this would compromise treatment.^3,6,2

Coordinate maternal, fetal and neonatal care

Continue maternal and fetal monitoring, involve anaesthesia and neonatology, correct physiological deterioration, and use NICE NG25 for any preterm-birth corticosteroid or magnesium-sulfate decision without delaying necessary birth.^5,3,2

Deliver safely and assess after birth

Arrange timely birth after maternal stabilisation; choose induction or caesarean according to obstetric circumstances rather than infection alone, document maternal antibiotics and apply NICE NG195 neonatal risk-management recommendations after birth.^1,3,7

Exam traps

A normal temperature or normal CRP does not exclude sepsis or intra-amniotic infection.
Do not wait for culture results before treating high-risk sepsis.
Do not use fetal tachycardia alone as diagnostic proof; interpret it with the maternal and clinical picture.
Do not choose caesarean birth solely because chorioamnionitis is present.
Do not continue routine expectant PPROM management when infection is suspected.
A suspected maternal infection still triggers a neonatal infection risk assessment even if chorioamnionitis is not confirmed.

Illustrations

Acute chorioamnionitis on histologyH&E histology of fetal membranes showing acute neutrophilic inflammation of the chorion and amnion, the pathological correlate of ascending intra-amniotic infection.Nephron, Wikimedia Commons · CC-BY-SA-3.0

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.