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ob.chorioamnionitis.v1PRODUCTION
ob.chorioamnionitis.v1

Chorioamnionitis / Intra-amniotic Infection (IAI) / Triple I

obstetricsacuteadultpregnancy
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12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Intrapartum / immediate-postpartum maternal infection-inflammation syndrome; renamed "Triple I" per Higgins NICHD/ACOG/SMFM 2016 + ACOG CO 712 2017. Partition by gestational age: term (≥ 37 wk, ~ 2-5% incidence) vs preterm (< 37 wk, ~ 25% incidence in preterm labor). Distinguishes from isolated maternal fever (single criterion; observe + investigate other causes) vs suspected Triple I (fever + ≥ 1 secondary criterion; empiric antibiotics) vs confirmed Triple I (with objective amniotic fluid evidence).

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GA cohort tagged; Higgins 2016 diagnostic category assigned

Patient inputs (20)

Maternal tachycardia > 100 is a Triple I supportive criterion (legacy chorio criteria; reduced sensitivity in Higgins 2016)

Tachypnea > 22 is qSOFA component; pregnant baseline ~ 16-22 so > 24 is concerning (SSC 2026)

Hypoxemia in pregnancy raises suspicion for atypical sepsis (pulmonary embolism mimic, AFE) or pneumonia source (separate dx)

FHR > 160 sustained × 10 min is Higgins 2016 suspected Triple I criterion; informs delivery urgency

ROM > 18 h is a CDC IAP indication + chorio risk factor; drives empiric antibiotic timing decision

Repeated cervical exams after ROM increase ascending-infection risk dose-response (Newton 1993; Tita Andrews 2010)

GBS-positive antepartum screen with inadequate or no intrapartum prophylaxis raises neonatal EOS risk; informs newborn pathway per CDC Verani 2010 + AAP Puopolo 2018

Single ≥ 39.0 °C OR 38.0-38.9 °C × 2 ≥ 30 min apart is the gateway criterion (Higgins 2016)

Term ≥ 37 wk (~ 2-5% chorio incidence) vs preterm < 37 wk (~ 25% chorio incidence in preterm labor); preterm chorio drives neonatal NICU planning + steroid + magnesium decisions

WBC > 15K without steroids is Higgins 2016 suspected Triple I criterion; baseline + trend in postpartum endometritis surveillance

Pyelonephritis is a common chorio mimic in pregnancy — rule out with UA + urine culture

Renal function for dosing + sepsis organ dysfunction (creatinine ≥ 2× baseline → KDIGO AKI; sepsis-AKI cross-reference)

Hypotension is a sepsis flag — drives routing to id.sepsis.core.v1; MAP < 65 in pregnant patient demands rapid resuscitation (SSC 2026 with OB adaptation)

Anaphylaxis vs mild allergy drives substitute regimen: anaphylaxis → vancomycin + gentamicin; mild → cefazolin + gentamicin (ACOG CO 712 2017; ACOG CO 797 2020)

Cesarean vs vaginal drives anaerobic coverage decision (clindamycin or metronidazole add-on for cesarean to prevent postpartum endometritis)

Amniotic fluid Gram stain, culture, glucose < 14 mg/dL, IL-6 elevated define confirmed Triple I (Higgins 2016); amniocentesis rare intrapartum but used selectively

Rule out pneumonia source (community-acquired or aspiration) if cough / desaturation / focal exam (separate dx pathway via pulm.cap.core.v1)

Recurrent chorio in subsequent pregnancy informs surveillance + microbiome considerations; not a treatment modifier per se

Bacteremia in chorio ~ 5-10%; mandatory if SIRS / qSOFA features (sepsis pathway carryover)

Lactate > 2 with infection is a sepsis flag; drives routing to id.sepsis.core.v1 (SSC 2026 Hour-1 bundle)

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Severity triggers (10)

10 need judgement
  • informationallife_threateningchorioamnionitis_with_maternal_sepsis_features
    Chorioamnionitis + maternal qSOFA ≥ 2 OR SIRS ≥ 2 OR lactate ≥ 2 OR hypotension MAP < 65 — life-threatening maternal sepsis; routes to id.sepsis.core.v1 with OB-specific carryover. Broaden empirics (piperacillin-tazobactam or meropenem ± vancomycin) and emergent delivery (chorio source IS the gravid uterus).
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationallife_threateningsevere_chorio_in_pregnancy_requires_icu
    Severe chorio with pulmonary edema OR shock OR multi-organ dysfunction OR ARDS-pattern → ICU + broad-spectrum + emergent delivery + multidisciplinary critical care + OB + neonatology
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseveredelayed_delivery_with_chorio_after_antibiotics
    Chorio with antibiotics administered + persistent or progressive features + no delivery progress > 6 h post-antibiotic → consider cesarean. Each hour of delivery delay after chorio diagnosis correlates with increased maternal + neonatal morbidity (Tita Andrews 2010).
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseveregbs_positive_no_intrapartum_prophylaxis_with_chorio
    GBS-positive antepartum screen + inadequate intrapartum prophylaxis + maternal chorio → newborn at very high risk for early-onset GBS sepsis; mandatory newborn-care notification + neonatal empirics + sepsis surveillance per AAP Puopolo 2018; routes to id.neonatal-sepsis.early-late.v1.
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverepostpartum_endometritis_emerging
    Postpartum fever > 24-48 h OR uterine tenderness OR foul/purulent lochia → endometritis emerging; broaden anaerobic coverage; ddx retained products + abscess + cesarean wound infection
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverepreterm_chorio_with_neonatal_workup_required
    Preterm (< 37 wk) gestation + maternal chorio → neonatal workup mandatory due to elevated EOS + intraventricular hemorrhage + cerebral palsy + bronchopulmonary dysplasia risk; broaden neonatal empirics and admit NICU; routes to id.neonatal-sepsis.early-late.v1.
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalseverecesarean_delivery_post_chorio_extended_abx
    Cesarean delivery + chorio → extended 48 h IV antibiotic continuation postpartum + anaerobic add-on (clindamycin or metronidazole) for endometritis prevention; transition to PO not typically needed if course complete inpatient
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderaterecurrent_chorio_subsequent_pregnancy
    Prior chorio in previous pregnancy → ~ 5-15% recurrence risk in subsequent pregnancy; aspirin NOT specifically indicated (PPRO risk reduction is different population); close intrapartum surveillance; vaginal microbiome considerations (emerging research; no formal intervention yet)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderatepen_allergy_with_chorio_intrapartum
    Maternal penicillin allergy + intrapartum chorio → substitute regimen by allergy severity: severe anaphylaxis → vancomycin + gentamicin; mild allergy without anaphylaxis → cefazolin + gentamicin (cross-reactivity ~ 1-2%, ACOG CO 712 2017)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmildintra_amniotic_inflammation_without_infection_diagnosis
    Sterile intra-amniotic inflammation per Higgins 2016 categories (elevated IL-6, no positive cultures, no Gram-stain positivity); treat conservatively with surveillance but maintain high index for transition to overt infection
    Trigger could not be auto-evaluated — needs clinician judgement.

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Recommended regimen

Intrapartum + postpartum empiric antibiotics for chorioamnionitis / Triple I (ACOG CO 712 2017)
axis: chorioamnionitis_empiric_antibioticsstep intrapartum_standard_no_allergy - Intrapartum standard regimen — no penicillin allergy (ACOG CO 712 2017)
Selected step "Intrapartum standard regimen — no penicillin allergy (ACOG CO 712 2017)" — Suspected or confirmed Triple I per Higgins 2016 + no severe penicillin allergy + intrapartum / not-yet-delivered
  • ampicillin
    first line
    aminopenicillin
    2 g IV • IV • q6h
    triggers: triple_i_recognition_no_pen_anaphylaxis
    Covers GBS, Listeria (cephalosporins do not), sensitive E. coli — ACOG CO 712 2017 first-line intrapartum
    rxcui 733
  • gentamicin
    first line
    aminoglycoside
    1.5 mg/kg IV q8h OR 5 mg/kg IV q24h (extended-interval) • IV • q8h or q24h
    triggers: triple_i_recognition
    Gram-negative synergy with ampicillin; once-daily extended-interval also acceptable; ACOG CO 712 2017
    rxcui 1596450

outpatient playbook — drug actions (5)

  1. 1. iron repletion if postpartum anemia
    rxcui 24947
    Ferrous sulfate 325 mg PO TID; IV iron if severe anemia (Hgb < 8) or non-tolerant • PO/IV • TID PO or per infusion protocol
    trigger: Postpartum Hgb < 11 g/dL
    Restore iron stores; reduce fatigue + improve recovery (ACOG general postpartum guidance)
  2. 2. contraception
    Per ACOG MEC + patient preference (LARC, COC, POP, DMPA, etc.) • PO/IM/implant/IUD • per agent
    trigger: Patient request + medical eligibility
    Avoid short interpregnancy interval (< 18 mo associated with worse outcomes including recurrent chorio); ACOG MEC
  3. 3. influenza vaccine
    0.5 mL IM • IM • annual in season
    trigger: Postpartum in flu season; vaccination of family contacts
    Standard ACIP recommendation
  4. 4. COVID-19 vaccine per ACIP
    Per current ACIP • IM • per current guidance
    trigger: Per current schedule
    Per current ACIP
  5. 5. Tdap if not given in 3rd trimester
    0.5 mL IM × 1 • IM • once postpartum if not done antenatally
    trigger: Tdap not given in pregnancy (ACOG recommends 27-36 wk)
    Protect neonate from pertussis; ACIP + ACOG standard

Auto-drafted A&P note

outpatient

Subjective

- Possible entry pathways: Intrapartum maternal fever — single ≥ 39.0 °C OR 38.0-38.9 °C confirmed × 2 ≥ 30 min apart (Higgins NICHD/ACOG/SMFM 2016 Obstet Gynecol 127:426); Sustained fetal heart rate > 160 bpm for ≥ 10 min on continuous EFM with maternal fever (Higgins 2016; ACOG CO 712 2017); Maternal WBC > 15,000/µL without antenatal corticosteroid exposure + maternal fever (Higgins 2016).

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Chorioamnionitis / Intra-amniotic Infection (IAI) / Triple I** (ob.chorioamnionitis.v1).
Phenotype framing: Pyelonephritis (UA + urine culture), influenza (PCR if season), COVID-19 (PCR), appendicitis (atypical RLQ in pregnancy), pneumonia (CXR), DVT / PE (Doppler + d-dimer caveats in pregnancy), epidural-related fever (common with > 4 h labor epidural; non-infectious), drug fever, pre-eclampsia with HELLP (overlap; ALT/AST + platelets + UA protein), amniotic fluid embolism (AFE; sudden hypoxia + hypotension + DIC at delivery — emergent), isolated maternal fever (Higgins 2016 — single criterion alone, not yet Triple I).
Scope: Intrapartum / immediate-postpartum maternal infection-inflammation syndrome; renamed "Triple I" per Higgins NICHD/ACOG/SMFM 2016 + ACOG CO 712 2017. Partition by gestational age: term (≥ 37 wk, ~ 2-5% incidence) vs preterm (< 37 wk, ~ 25% incidence in preterm labor). Distinguishes from isolated maternal fever (single criterion; observe + investigate other causes) vs suspected Triple I (fever + ≥ 1 secondary criterion; empiric antibiotics) vs confirmed Triple I (with objective amniotic fluid evidence).

No severity triggers fired against current inputs.

Plan

Regimen axis: **Intrapartum + postpartum empiric antibiotics for chorioamnionitis / Triple I (ACOG CO 712 2017)** — step "Intrapartum standard regimen — no penicillin allergy (ACOG CO 712 2017)".
1. ampicillin 2 g IV IV q6h (aminopenicillin, first line) — Covers GBS, Listeria (cephalosporins do not), sensitive E. coli — ACOG CO 712 2017 first-line intrapartum
2. gentamicin 1.5 mg/kg IV q8h OR 5 mg/kg IV q24h (extended-interval) IV q8h or q24h (aminoglycoside, first line) — Gram-negative synergy with ampicillin; once-daily extended-interval also acceptable; ACOG CO 712 2017

Setting playbook (outpatient) — Routine postpartum 6-week visit + chorio-specific anticipatory guidance (recurrence risk, microbiome / probiotic emerging research, mental health, contraception, immunization) + newborn outpatient peds 24-48 h post-discharge with high-risk-followup; longitudinal tracking for future-pregnancy planning
3. iron repletion if postpartum anemia Ferrous sulfate 325 mg PO TID; IV iron if severe anemia (Hgb < 8) or non-tolerant PO/IV TID PO or per infusion protocol — Postpartum Hgb < 11 g/dL (Restore iron stores; reduce fatigue + improve recovery (ACOG general postpartum guidance))
4. contraception Per ACOG MEC + patient preference (LARC, COC, POP, DMPA, etc.) PO/IM/implant/IUD per agent — Patient request + medical eligibility (Avoid short interpregnancy interval (< 18 mo associated with worse outcomes including recurrent chorio); ACOG MEC)
5. influenza vaccine 0.5 mL IM IM annual in season — Postpartum in flu season; vaccination of family contacts (Standard ACIP recommendation)
6. COVID-19 vaccine per ACIP Per current ACIP IM per current guidance — Per current schedule (Per current ACIP)
7. Tdap if not given in 3rd trimester 0.5 mL IM × 1 IM once postpartum if not done antenatally — Tdap not given in pregnancy (ACOG recommends 27-36 wk) (Protect neonate from pertussis; ACIP + ACOG standard)

Non-pharmacologic actions:
- Mental health counseling / therapy if EPDS ≥ 10 or PCL-5 elevated
- Lactation continued support if breastfeeding (chorio antibiotics not contraindicated with breastfeeding per LactMed)
- Postpartum exercise progression per ACOG (8 wks to gradual return; immediate light activity OK)
- Future-pregnancy preconception counseling — encourage 18+ mo interpregnancy interval, optimize maternal health (DM, weight, smoking, periodontal health), early GBS / chorio risk awareness
- Pediatric follow-up coordination for high-risk newborn — 24-48 h post-discharge peds visit, then 1 wk + 1 mo developmental + immunization tracking
- Vaginal microbiome / probiotic research awareness (no formal intervention recommended yet)

AVOID / contraindication checks:
- NSAIDs avoid intrapartum PDA constriction and bleeding (ACOG CO 712 2017)
- Ceftriaxone avoid neonatal period bilirubin displacement (AAP Puopolo 2018 — affects newborn handoff, not maternal regimen per se)
- Gentamicin extended interval acceptable once daily 5mg per kg q24h (ACOG CO 712 2017)
- Vancomycin AUC target not trough (Rybak IDSA 2020 PMID 32191793)
- Cephalosporin cross reactivity low 1 to 2 percent in mild pen allergy (Macy 2014; ACOG CO 712 2017)
- Delivery is definitive treatment do not delay for antibiotics (ACOG CO 712 2017)
- Avoid fluid overload in chorio pulmonary edema risk especially with pre eclampsia overlap (SSC 2026 OB adaptation)

Monitoring

Regimen monitoring:
- Maternal temperature q1-2h intrapartum then q4h postpartum (ACOG CO 712 2017)
- Continuous fetal monitoring intrapartum until delivery (Category I/II/III interpretation)
- CBC + CMP daily until afebrile + improving
- Maternal blood culture follow-up at 48-72 h if persistent fever
- Gentamicin trough before 3rd dose target < 2 mcg/mL OR AUC-monitored (extended-interval)
- Vancomycin AUC q48-72h (or trough 15-20 if AUC unavailable, IDSA 2020 PMID 32191793)
- Fundal tone q4h postpartum (atony surveillance — chorio increases atony risk)
- Lochia + uterine tenderness q4h postpartum (endometritis surveillance)
- Newborn handoff: chorio diagnosis + IAP timing + antibiotic regimen → pediatric / neonatal team (AAP Puopolo 2018)

Setting (outpatient) monitoring:
- 6-week postpartum visit; additional visit at 1-2 wk if cesarean wound concern
- Newborn outpatient peds at 24-48 h then 1 wk then 1 mo
- Maternal mental health re-screen at 6 wk + 3 mo + 6 mo
- Future-pregnancy preconception visit when contemplated

Follow-up plan: Routine 6-week postpartum visit + chorio-specific anticipatory guidance: recurrence risk in subsequent pregnancy (~ 5-15%), microbiome / vaginal flora considerations (probiotic + targeted prevention research ongoing), mental health screen (PPD + postpartum-PTSD higher with peripartum complications), breastfeeding support, contraception counseling, immunization review (Tdap if not given, influenza, COVID per ACIP). Newborn outpatient: 24-48 h post-discharge peds visit if maternal chorio (high-risk follow-up).
- Close-out criterion: Postpartum visit documented; future-pregnancy counseling delivered; newborn followup arranged

Monitoring phase: Intrapartum: continuous EFM (Category I/II/III), maternal vitals q15 min, fetal scalp pH if Category III, response to antipyretic + antibiotics. Postpartum: vitals q4h × 24 h then per protocol, fundal tone q4h (atony risk elevated in chorio), lochia + uterine tenderness assessment q4h (endometritis surveillance), CBC + CMP daily until afebrile, repeat blood culture at 48-72 h if persistent fever, lactation support, VTE prophylaxis once postpartum bleeding stable.

Disposition

Current setting: outpatient — Routine postpartum 6-week visit + chorio-specific anticipatory guidance (recurrence risk, microbiome / probiotic emerging research, mental health, contraception, immunization) + newborn outpatient peds 24-48 h post-discharge with high-risk-followup; longitudinal tracking for future-pregnancy planning

Disposition criteria:
- Resolution: 6-wk postpartum visit complete, mental health stable, contraception in place, immunizations up to date, newborn developmental tracking ongoing → discharge from chorio-specific surveillance back to routine primary care + preconception planning

Escalation triggers (move to higher acuity):
- Postpartum fever / chills / uterine tenderness / foul lochia → endometritis workup (ED visit + broad-spectrum + imaging)
- New mental health crisis (PHQ-9 ≥ 15 or suicidal ideation) → urgent mental health referral
- Newborn high-risk features (persistent fever, poor feeding, irritability) → urgent peds visit / ED
- Cesarean wound concern (erythema, dehiscence, purulent drainage) → urgent OB visit

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Chorioamnionitis + maternal qSOFA ≥ 2 OR SIRS ≥ 2 OR lactate ≥ 2 OR hypotension MAP < 65 — life-threatening maternal sepsis; routes to id.sepsis.core.v1 with OB-specific carryover. Broaden empirics (piperacillin-tazobactam or meropenem ± vancomycin) and emergent delivery (chorio source IS the gravid uterus).
- [LIFE_THREATENING] Severe chorio with pulmonary edema OR shock OR multi-organ dysfunction OR ARDS-pattern → ICU + broad-spectrum + emergent delivery + multidisciplinary critical care + OB + neonatology
- [SEVERE] Chorio with antibiotics administered + persistent or progressive features + no delivery progress > 6 h post-antibiotic → consider cesarean. Each hour of delivery delay after chorio diagnosis correlates with increased maternal + neonatal morbidity (Tita Andrews 2010).

Citations

- ACOG Committee Opinion 712 (2017, reaffirmed 2022) — Intrapartum Management of Intraamniotic Infection + Higgins RD et al, NICHD/ACOG/SMFM 2016 workshop (Obstet Gynecol 127:426; PMID 26855098) + ACOG Practice Bulletin 188 (2018) Prelabor Rupture of Membranes + ACOG Committee Opinion 797 (2020) Prevention of GBS Early-Onset Disease + WHO 2015 Recommendations for prevention and treatment of maternal peripartum infections + AAP Puopolo 2018 newborn EOS framework (PMID 30455342, 30455344) + CDC Verani 2010 GBS prevention (PMID 21088663) + SSC 2026 (sepsis-pathway carryover when maternal SIRS / qSOFA) [PMID:26855098](https://pubmed.ncbi.nlm.nih.gov/26855098/)
- Cited evidence (PMID 30455342) [PMID:30455342](https://pubmed.ncbi.nlm.nih.gov/30455342/)
- Cited evidence (PMID 30455344) [PMID:30455344](https://pubmed.ncbi.nlm.nih.gov/30455344/)
- Cited evidence (PMID 21088663) [PMID:21088663](https://pubmed.ncbi.nlm.nih.gov/21088663/)
- Cited evidence (PMID 20569811) [PMID:20569811](https://pubmed.ncbi.nlm.nih.gov/20569811/)

Last reconciled with current guidelines: 2026-05-15.
References
  • ACOG Committee Opinion 712 (2017, reaffirmed 2022) — Intrapartum Management of Intraamniotic Infection + Higgins RD et al, NICHD/ACOG/SMFM 2016 workshop (Obstet Gynecol 127:426; PMID 26855098) + ACOG Practice Bulletin 188 (2018) Prelabor Rupture of Membranes + ACOG Committee Opinion 797 (2020) Prevention of GBS Early-Onset Disease + WHO 2015 Recommendations for prevention and treatment of maternal peripartum infections + AAP Puopolo 2018 newborn EOS framework (PMID 30455342, 30455344) + CDC Verani 2010 GBS prevention (PMID 21088663) + SSC 2026 (sepsis-pathway carryover when maternal SIRS / qSOFA) — PMID:26855098
  • Cited evidence (PMID 30455342) — PMID:30455342
  • Cited evidence (PMID 30455344) — PMID:30455344
  • Cited evidence (PMID 21088663) — PMID:21088663
  • Cited evidence (PMID 20569811) — PMID:20569811