Postpartum Endometritis

1. Clinical Overview

Answer Card Summary

Postpartum endometritis is a polymicrobial infection of the uterine decidua, myometrium, and parametrial tissues occurring after delivery. It represents one of the most common causes of puerperal fever and remains a significant contributor to maternal morbidity and mortality globally. [1,2]

The condition is characterised by the classic triad: fever (> 38°C), uterine tenderness, and offensive lochia. Caesarean section is the single most important risk factor, increasing the risk 10-20 fold compared to vaginal delivery, with post-caesarean rates of 5-15% without antibiotic prophylaxis versus 1-3% after vaginal birth. [3,4]

The infection is typically polymicrobial, involving ascending organisms from the lower genital tract including Group A and B Streptococci, Gram-negative enteric bacteria (particularly E. coli), and anaerobes (Bacteroides, Peptostreptococcus). Group A Streptococcus (Streptococcus pyogenes) deserves special mention as it can cause fulminant, life-threatening sepsis with extremely rapid progression. [5,6]

Early recognition and treatment are critical. The mainstay of management is broad-spectrum intravenous antibiotics covering Gram-positive, Gram-negative, and anaerobic organisms. The gold standard regimen is clindamycin plus gentamicin, which provides cure rates exceeding 90%. [7,8] Failure to respond within 48-72 hours mandates investigation for complications including retained products of conception, pelvic abscess, or septic pelvic thrombophlebitis.

Prevention is highly effective: prophylactic antibiotics administered at the time of caesarean section (preferably before skin incision) reduce endometritis rates by approximately 60-70%. [9] This intervention represents one of the most cost-effective preventive measures in obstetric practice.

Key Facts

Clinical Pearls

"The Caesarean Consequence": Caesarean section carries a 10-20 fold increased risk of endometritis compared to vaginal delivery. Always maintain high index of suspicion post-CS.

"GAS = Gas on the Fire": Group A Streptococcus can progress from mild symptoms to septic shock within hours. Early-onset (less than 24h) severe symptoms demand immediate aggressive treatment.

"The 5 T's of Postpartum Fever":

• Temperature (endometritis)
• Thrombophlebitis (pelvic/DVT)
• Trauma (wound infection, haematoma)
• Tissue (retained products of conception)
• Teat (mastitis/breast abscess)

"Sepsis 6 in 60 Minutes": Maternal sepsis requires immediate implementation of the Sepsis 6 bundle within one hour. Delay kills.

"Clinda-Gent is Gold": Clindamycin + gentamicin remains the gold standard combination, achieving > 90% cure rates in uncomplicated endometritis.

"Prevention Beats Cure": Pre-incision antibiotics at caesarean section reduce endometritis by 60-70% and represent one of the most cost-effective interventions in obstetrics.

"The 48-72 Hour Rule": Clinical improvement expected within 48-72 hours of IV antibiotics. No improvement mandates investigation for complications (retained products, abscess, resistant organisms).

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2. Epidemiology

Incidence and Prevalence

Postpartum endometritis represents the most common puerperal infection and a leading cause of postpartum fever worldwide. [1,10]

Geographic Variation: Rates are higher in low-resource settings where access to prophylactic antibiotics and sterile surgical technique may be limited. [11]

Risk Factors

Major Risk Factors (Highest Impact)

Moderate Risk Factors

• Multiple vaginal examinations (each exam ↑ risk by ~10-15%)
• Internal fetal monitoring (scalp electrode, intrauterine pressure catheter)
• Chorioamnionitis during labour (3-4x increased risk)
• Bacterial vaginosis (2-3x increased risk)
• Group B Streptococcus colonisation (2x increased risk)
• Meconium-stained liquor (possible immune response alteration)

Patient-Specific Risk Factors

Procedural Risk Factors

• Longer operative time (each additional 30 minutes ↑ risk by ~20%)
• Lack of antibiotic prophylaxis at caesarean (5-7x increased risk vs prophylaxis)
• Pre-labour caesarean vs post-labour (lower risk electively)
• Vaginal preparation with antiseptics (protective - reduces risk by ~40%)
• Removal of placenta by controlled cord traction vs manual removal

Exam Detail: ### MRCOG High-Yield Points

Exam Favourite: "What is the single most important risk factor for postpartum endometritis?" Answer: Caesarean section (10-20 fold increased risk compared to vaginal delivery)

Viva Question: "Why does emergency caesarean in labour carry higher infection risk than elective pre-labour caesarean?" Model Answer: Emergency CS in labour combines multiple risk factors:

1. Prolonged labour with tissue trauma and oedema
2. Prolonged rupture of membranes allowing ascending infection
3. Multiple vaginal examinations introducing organisms
4. Possible chorioamnionitis already present
5. Urgency may compromise sterile technique
6. Surgical difficulty due to oedematous, vascular tissues

Demographics

Age Distribution: More common in younger women (less than 25 years), possibly related to cervical immunity and bacterial colonisation patterns. [14]

Parity: Nulliparous women have higher rates (associated with higher caesarean and instrumental delivery rates).

Ethnicity: Some studies suggest higher rates in certain ethnic groups, but this is confounded by socioeconomic factors and access to healthcare. [11]

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3. Aetiology and Pathophysiology

Microbiological Aetiology

Postpartum endometritis is polymicrobial in 60-70% of cases, reflecting ascending infection from the normal vaginal flora that becomes pathogenic in the postpartum uterine environment. [5,15]

Common Organisms (Polymicrobial Pattern)

Group A Streptococcus: The Most Feared Pathogen

Group A Streptococcus (Streptococcus pyogenes) deserves special emphasis due to its capacity to cause fulminant, life-threatening sepsis. [6,16]

Key Features of GAS Endometritis:

• Rapid progression: Can progress from mild symptoms to septic shock within 12-24 hours
• Early onset: Typically presents within 24-48 hours postpartum (vs 3-5 days for typical endometritis)
• Severe systemic toxicity: High fever, tachycardia, hypotension, confusion
• Complications: Streptococcal toxic shock syndrome (STSS), necrotising fasciitis, bacteraemia
• Mortality: Up to 50-60% if diagnosis delayed; requires aggressive treatment

Virulence Factors:

• M protein (antiphagocytic)
• Streptolysin O and S (cytotoxic)
• Streptococcal pyrogenic exotoxins (superantigens → toxic shock)
• Hyaluronidase, DNase, streptokinase (tissue invasion)

Treatment Implications:

• Immediate broad-spectrum antibiotics (do NOT wait for cultures)
• Add high-dose penicillin (GAS is exquisitely sensitive; clindamycin for toxin suppression)
• Clindamycin suppresses toxin production (important in severe GAS infection)
• Consider IVIG in streptococcal toxic shock syndrome
• Early surgical intervention if necrotising fasciitis suspected

Pathophysiological Mechanism

Stage 1: Breach of Natural Barriers (Delivery)

Normal pregnancy and delivery create conditions favouring infection:

1. Cervical dilation → Loss of cervical mucus plug (protective barrier)
2. Vaginal delivery trauma → Tears, abrasions, haematomas (bacterial entry points)
3. Caesarean section → Direct breach of sterile peritoneal cavity
4. Placental separation → Large raw endometrial surface (ideal culture medium)
5. Lochia → Blood, decidual tissue, bacteria (rich growth medium)

Stage 2: Bacterial Ascent and Colonisation

Normal vaginal flora (lactobacilli-dominant, pH 3.8-4.5) ascends into the:

• Endometrial cavity (normally sterile in pregnancy)
• Myometrium (if deep tissue invasion occurs)
• Parametrium (via lymphatic spread)

Post-delivery changes favour infection:

• Loss of mucus plug → loss of mechanical barrier
• Alkaline lochia (pH 7.0-7.5) → loss of acidic protection
• Devitalised tissue and blood clots → bacterial nidus
• Uterine atony → reduced clearance of infected material

Stage 3: Tissue Invasion and Inflammation

Polymicrobial synergy: Aerobes consume oxygen → create anaerobic environment → anaerobes flourish

Inflammatory cascade:

1. Bacterial invasion of decidua and myometrium
2. Neutrophil recruitment and degranulation
3. Cytokine release (IL-1, IL-6, TNF-α)
4. Fever, tachycardia, systemic inflammatory response
5. If unchecked → sepsis → multi-organ dysfunction

Local tissue effects:

• Endometrial and myometrial inflammation and necrosis
• Uterine tenderness and subinvolution
• Parametrial cellulitis (extension beyond uterus)
• Foul-smelling lochia (anaerobic metabolism)

Stage 4: Potential Complications (If Untreated)

Local extension:

• Parametritis → pelvic cellulitis
• Pelvic abscess → tubo-ovarian abscess, pelvic collection
• Peritonitis → generalised abdominal sepsis
• Septic pelvic thrombophlebitis → ovarian vein or pelvic vein thrombosis with septic emboli

Systemic complications:

• Bacteraemia → positive blood cultures
• Sepsis → SIRS criteria, lactate > 2 mmol/L
• Septic shock → hypotension requiring vasopressors
• Multi-organ dysfunction → acute kidney injury, ARDS, DIC, liver dysfunction
• Death → particularly with GAS, delayed treatment, or immunocompromise

Exam Detail: ### Molecular Pathophysiology (Postgraduate Level)

Bacterial Virulence and Host Response

Toll-Like Receptor (TLR) Activation:

• TLR2 and TLR4 recognise bacterial lipopolysaccharide (LPS) and peptidoglycan
• Activation of NF-κB pathway → transcription of pro-inflammatory cytokines
• IL-1β, IL-6, IL-8, TNF-α release → fever, tachycardia, leucocytosis

Complement Activation:

• Classical and alternative pathways activated by bacterial components
• C3a, C5a (anaphylatoxins) → vasodilation, increased permeability
• Opsonisation (C3b) → enhanced phagocytosis

Coagulation Cascade:

• Tissue factor expression → activation of extrinsic pathway
• Thrombin generation → fibrin deposition, microvascular thrombosis
• DIC in severe sepsis → consumption of clotting factors and platelets

Endotoxin and Superantigens:

• Gram-negative endotoxin (LPS) → massive cytokine release
• GAS streptococcal pyrogenic exotoxins → T-cell activation (bypassing normal antigen presentation)
• Toxic shock syndrome → capillary leak, hypotension, multi-organ failure

Role of Retained Products of Conception

Retained placental tissue is found in 5-15% of cases of postpartum endometritis, particularly those failing to respond to initial antibiotic therapy. [13]

Mechanisms:

• Physical nidus for bacterial colonisation
• Ongoing inflammation and tissue necrosis
• Prevention of normal uterine involution
• Sustained endometrial surface (unable to re-epithelialise)

Clinical Clues to RPOC:

• Persistent or heavy vaginal bleeding
• Uterine subinvolution (large, soft uterus)
• Failure to respond to appropriate antibiotics within 48-72 hours
• Ultrasound: heterogeneous endometrial material, increased vascularity on Doppler

Management:

• Surgical evacuation (suction curettage)
• Medical management (misoprostol) less reliable in infected setting
• Antibiotics alone insufficient

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4. Clinical Presentation

Symptoms

Cardinal Symptoms

Associated Symptoms

• Rigors and chills (especially with bacteraemia)
• Headache
• Myalgia
• Anorexia
• Nausea (less common; consider other diagnoses if prominent)
• Dysuria (may indicate concurrent UTI)

Timing of Presentation

Signs

Vital Signs

General Examination

• Appearance: Unwell, flushed, sweaty
• Hydration: May be dehydrated (reduced skin turgor, dry mucous membranes)
• Peripheral perfusion: Warm peripheries (early sepsis) vs cold, mottled (shock)
• Level of consciousness: Alert vs confused/drowsy (cerebral hypoperfusion)

Abdominal Examination

Inspection:

• Caesarean wound: erythema, discharge, dehiscence (wound infection vs endometritis)
• Distension (if peritonitis or ileus developing)

Palpation:

• Uterine fundal height: Should involute ~1 cm/day; Subinvolution suggests infection or retained products
• Uterine tenderness: Suprapubic tenderness on palpation of uterine fundus (pathognomonic sign)
• Uterine consistency: Should firm with involution; Boggy, soft uterus suggests atony or retained products
• Peritonism: Guarding, rigidity, rebound tenderness (suggests peritonitis - severe)

Percussion: Dullness if pelvic collection/abscess

Auscultation: Bowel sounds (may be reduced if ileus developing)

Vaginal/Speculum Examination

Speculum examination:

• Lochia assessment:
  • "Colour: normally lochia rubra (red) days 1-3 → lochia serosa (pink) days 4-10 → lochia alba (white) days 10-14"
  • Offensive odour (key diagnostic feature - anaerobes)
  • Purulent appearance
  • Excessive volume or persistence of heavy bleeding
• Cervical os: May be open (allows bacterial ascent and lochial drainage)
• Cervix: Tenderness, purulent discharge from os
• Vaginal walls: Erythema, discharge

Bimanual examination:

• Uterine size: Larger than expected for days postpartum
• Uterine tenderness: Moderate to severe on bimanual palpation
• Cervical excitation: Pain on moving cervix
• Adnexal masses: Suggests tubo-ovarian abscess (complication)
• Parametrial induration: Suggests parametritis (pelvic cellulitis)

Red Flag Features (Sepsis/Severe Infection)

Immediate escalation and aggressive management required if:

• Systolic BP less than 90 mmHg or MAP less than 65 mmHg
• Heart rate > 130 bpm
• Altered mental status (confusion, agitation, reduced GCS)
• Lactate > 2 mmol/L (tissue hypoperfusion)
• Respiratory rate > 25/min or SpO₂ less than 92%
• Urine output less than 0.5 mL/kg/h
• Mottled or cold peripheries (poor perfusion)
• Temperature > 39.5°C or less than 36°C
• Purpuric rash (meningococcus, GAS)

Exam Detail: ### OSCE/Clinical Examination Viva

Examiner: "You are called to see a 28-year-old woman on day 3 post-emergency caesarean section. She has a temperature of 38.7°C. Talk me through your assessment."

Model Answer:

"I would approach this systematically using an ABCDE assessment, keeping postpartum endometritis high in my differential given the timing and mode of delivery.

A and B: I'd assess airway patency and respiratory function - looking for any signs of respiratory compromise that might suggest sepsis or aspiration.

C: I'd assess circulation - heart rate, blood pressure, capillary refill, peripheral perfusion. I'm particularly concerned about tachycardia and hypotension which would suggest sepsis.

D: I'd assess consciousness level and look for confusion which could indicate cerebral hypoperfusion in severe sepsis.

E: Full exposure and examination.

Specific assessment for postpartum fever:

I would use the '5 T's' framework:

1. Temperature (endometritis) - my primary concern here
2. Thrombophlebitis - pelvic veins, DVT, superficial thrombophlebitis
3. Trauma - wound infection, haematoma, perineal trauma
4. Tissue - retained products of conception
5. Teat - mastitis or breast abscess

For endometritis specifically, I would:

• Examine the abdomen: assess uterine fundal height, palpate for uterine tenderness (key sign), check for peritonism
• Examine the caesarean wound for signs of infection
• Perform a speculum and bimanual examination: assess lochia (colour, odour, volume), check for uterine tenderness on bimanual palpation, assess uterine size and consistency

Red flags I'm looking for:

• Signs of sepsis: HR > 130, BP less than 90, altered consciousness, mottled skin
• Signs of necrotising fasciitis: severe pain out of proportion, crepitus, skin changes
• Very early onset (less than 24h) suggesting Group A Strep

Investigations I would request:

• Septic screen: blood cultures, high vaginal swab, FBC, CRP, lactate, U&Es, LFTs
• Imaging: pelvic ultrasound to assess for retained products

Management:

• If sepsis suspected: immediate Sepsis 6 within one hour
• Broad-spectrum IV antibiotics: clindamycin + gentamicin
• Senior review and HDU/ITU assessment if haemodynamically unstable"

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5. Differential Diagnosis

Postpartum fever ("puerperal pyrexia") has multiple causes. Systematic evaluation is essential.

The "5 T's" Framework

Detailed Differential Diagnosis

Genital Tract Causes

1. Caesarean Section Wound Infection

• Erythema, warmth, discharge from wound
• Wound tenderness and induration
• May have wound dehiscence
• Usually day 4-7 postpartum
• Distinguish from endometritis: localised to wound; no uterine tenderness; no offensive lochia

2. Perineal Wound Infection

• Following episiotomy or perineal tear
• Perineal pain, discharge, breakdown
• Distinguish from endometritis: localised perineal signs; no uterine tenderness

3. Retained Products of Conception

• Persistent heavy vaginal bleeding
• Subinvolution of uterus
• Open cervical os
• Ultrasound: heterogeneous endometrial contents
• Often coexists with endometritis (may be the cause)

4. Pelvic Abscess

• Persistent fever despite antibiotics
• Severe pelvic pain
• Adnexal mass on examination
• Complication of untreated endometritis

5. Septic Pelvic Thrombophlebitis

• "Spiking fevers" despite appropriate antibiotics
• May have pelvic or leg vein thrombosis
• Diagnosis of exclusion
• CT/MRI may show thrombus in ovarian or pelvic veins

Extra-Genital Causes

6. Urinary Tract Infection / Pyelonephritis

• Dysuria, frequency, urgency
• Loin pain and tenderness (pyelonephritis)
• Distinguish from endometritis: urinary symptoms; loin tenderness; pyuria on urinalysis
• MSU: leucocytes, nitrites, culture

7. Mastitis / Breast Abscess

• Unilateral breast pain, erythema, tenderness
• Focal area of hardness
• Fever, malaise
• Fluctuant mass if abscess
• Distinguish from endometritis: localised to breast; no uterine/pelvic signs
• Usually day 5-21 postpartum (later than endometritis)

8. Deep Vein Thrombosis

• Unilateral leg swelling, calf tenderness, warmth
• Homan's sign (unreliable)
• Low-grade fever (vs high fever in infection)
• D-dimer elevated (but also elevated postpartum normally)
• Doppler ultrasound diagnostic

9. Pulmonary Embolism

• Chest pain, dyspnoea, haemoptysis
• Tachycardia, tachypnoea, hypoxia
• May have fever (low-grade)
• CTPA diagnostic

10. Pneumonia

• Cough, sputum, dyspnoea
• Respiratory signs on examination
• Chest X-ray shows consolidation
• Post-operative patients at risk (atelectasis, aspiration)

11. Drug Fever

• Fever without clear source
• Recent antibiotic or drug exposure
• Diagnosis of exclusion
• Fever resolves on discontinuing offending agent

Comparison Table: Endometritis vs Common Mimics

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6. Investigations

Initial Assessment

Bedside Tests

Blood Tests

Essential Initial Tests:

Blood Cultures:

• CRITICAL: Take before starting antibiotics if possible (but do NOT delay antibiotics if septic)
• Take 2 sets (aerobic and anaerobic bottles) from different sites
• Positive in 10-20% of endometritis cases
• Mandatory if sepsis suspected
• Identify causative organism and guide targeted therapy

Microbiological Samples

High Vaginal Swab / Endocervical Swab:

Technique:

• Sterile speculum examination
• Collect from posterior fornix (HVS) and endocervix
• Use charcoal swab for anaerobes
• Limitations: Contamination with normal vaginal flora common; Does NOT reliably reflect endometrial organisms

Interpretation:

• Heavy growth of potential pathogens (GAS, GBS, E. coli, Bacteroides)
• Important: Empirical treatment should NOT be delayed awaiting culture results
• Culture results guide narrowing or changing antibiotics if no response

Blood Cultures (see above)

Endometrial Culture (Rare):

• Obtained via transcervical endometrial biopsy or aspiration
• Rarely performed due to:
  • Risk of contamination
  • Invasiveness
  • Does not change immediate management
• May be considered in research settings or refractory cases

Imaging

Pelvic Ultrasound (Transvaginal and Transabdominal):

Indications:

• All patients with suspected endometritis (especially if no response to antibiotics)
• Assess for retained products of conception
• Exclude pelvic abscess or haematoma

Findings:

Limitations of Ultrasound:

• Cannot definitively diagnose endometritis (clinical diagnosis)
• Postpartum uterus appearances vary widely
• Distinguishing retained products from blood clot difficult

CT Pelvis (Contrast-Enhanced):

Indications:

• Persistent fever despite appropriate antibiotics
• Suspicion of pelvic abscess not clearly seen on USS
• Necrotising fasciitis suspected (surgical emergency)
• Septic pelvic thrombophlebitis

Findings:

• Abscess: rim-enhancing collection
• Gas in soft tissues (necrotising fasciitis - EMERGENCY)
• Thrombus in ovarian or pelvic veins (septic thrombophlebitis)
• Free fluid, inflammatory stranding

MRI Pelvis:

• Superior soft tissue contrast to CT
• Useful for delineating complex collections
• Septic pelvic thrombophlebitis
• No radiation (preferable if breastfeeding concerns)

Exam Detail: ### Investigation Interpretation: Exam Scenarios

Viva Question: "A woman on day 4 post-caesarean has fever 38.9°C and uterine tenderness. Her WCC is 11 × 10⁹/L. Does this exclude infection?"

Model Answer: "No, this does not exclude infection. There is a physiological leucocytosis postpartum (normal range ~10-15 × 10⁹/L), so a WCC of 11 may actually represent a relative neutrophilia compared to her baseline. I would interpret the WCC in the context of:

• The clinical picture (fever, uterine tenderness strongly suggest endometritis)
• CRP (more sensitive than WCC for infection)
• Trend of WCC (serial measurements)
• Other markers of sepsis (lactate, vital signs)

I would not withhold antibiotics based on a 'normal' WCC if the clinical suspicion is high."

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Viva Question: "Ultrasound shows 'heterogeneous endometrial contents 12mm thick' on day 5 postpartum in a febrile patient. What is your interpretation and management?"

Model Answer: "This is a challenging scenario as postpartum ultrasound findings are variable. The heterogeneous material could represent:

1. Retained placental tissue
2. Blood clot
3. Normal postpartum decidua and lochia

The key is clinical correlation:

• If she has heavy ongoing bleeding, subinvolution, and failure to respond to antibiotics → retained products likely → surgical evacuation indicated
• If she has minimal bleeding and is responding to antibiotics → likely clot or normal lochia → conservative management, repeat USS in 1 week

I would not routinely evacuate the uterus based on USS findings alone without clinical correlation, as this risks unnecessary intervention. However, if there is genuine RPOC and she's not responding to antibiotics, evacuation is both diagnostic and therapeutic."

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7. Management

Initial Assessment and Resuscitation (ABCDE)

Every patient with suspected postpartum endometritis requires systematic ABCDE assessment to identify sepsis.

A - Airway

• Assess patency
• Protect airway if reduced GCS
• High-flow oxygen if septic

B - Breathing

• Respiratory rate, oxygen saturations
• Auscultate chest (pulmonary oedema, pneumonia)
• ABG if hypoxic or tachypnoeic

C - Circulation

• Heart rate, blood pressure, capillary refill
• IV access (2 large-bore cannulae if septic)
• Fluid resuscitation if hypotensive (500 mL crystalloid bolus, reassess)
• Urine output monitoring (catheterise if septic)

D - Disability

• GCS, AVPU, blood glucose
• Confusion indicates cerebral hypoperfusion (severe sepsis)

E - Exposure

• Full examination including abdominal and pelvic assessment
• Temperature

Sepsis Recognition and Management

Sepsis 6 (Within 1 Hour if Sepsis Suspected)

"Sepsis 6" Bundle - critical time-dependent intervention: [17]

GIVE 3:

1. Oxygen - target SpO₂ 94-98% (or 88-92% if COPD)
2. IV fluids - 500 mL crystalloid bolus over 15 min, reassess
3. IV antibiotics - broad-spectrum, within 1 hour of recognition

TAKE 3: 4. Blood cultures - before antibiotics if possible, but do NOT delay treatment 5. Lactate - venous or arterial 6. Urine output - catheterise, target > 0.5 mL/kg/h

Escalation: Involve senior obstetrician, anaesthetist, critical care team early

Modified Early Obstetric Warning Score (MEOWS)

Obstetric patients physiologically different from general population - use MEOWS for monitoring:

• Triggers escalation at lower thresholds
• Accounts for normal pregnancy/postpartum physiology
• Mandatory regular observations (minimum 4-hourly; more frequent if unwell)

Antibiotic Therapy

First-Line Regimen: Clindamycin + Gentamicin (Gold Standard)

This combination is the gold standard endorsed by RCOG and international guidelines. [7,8,18]

Rationale for Combination:

• Clindamycin: anaerobes + Gram-positives
• Gentamicin: Gram-negatives
• Together: broad polymicrobial coverage
• Synergistic action
• Gentamicin penetrates biofilms

Duration:

• IV therapy until patient afebrile for 24-48 hours
• Then switch to oral if clinically improved (see oral regimens below)
• Total duration: typically 7-10 days (IV + oral combined)

Cure Rate: 90-95% for uncomplicated endometritis [7]

Alternative Regimens

If Clindamycin + Gentamicin Contraindicated or Unavailable:

If Penicillin Allergy:

• Mild allergy (rash): can often use cephalosporins or co-amoxiclav with caution
• Severe allergy (anaphylaxis): avoid β-lactams; use ciprofloxacin + metronidazole or aztreonam + clindamycin

Adding Ampicillin to Clindamycin + Gentamicin

Some guidelines recommend adding ampicillin for Enterococcal coverage:

Clindamycin + Gentamicin + Ampicillin ("Triple Therapy"):

• Ampicillin 2g IV q6h
• Covers Enterococcus (which clindamycin does not)
• Consider if:
  • No response to clindamycin + gentamicin after 48-72h
  • Enterococcus cultured
  • Severe sepsis

Evidence: Unclear benefit in uncomplicated endometritis; most guidelines use clindamycin + gentamicin first-line [8,18]

Group A Streptococcus-Specific Management

If GAS suspected or confirmed:

Add HIGH-DOSE PENICILLIN:

• Benzylpenicillin (Penicillin G) 2.4 g (4 million units) IV every 4 hours
• GAS is exquisitely sensitive to penicillin
• Continue clindamycin (suppresses toxin production - critical in severe GAS infection)

Rationale for Penicillin + Clindamycin:

• Penicillin: bactericidal against GAS
• Clindamycin: suppresses protein synthesis → reduces toxin production (streptococcal pyrogenic exotoxins)
• Synergistic effect in severe GAS infection [6,16]

Consider IVIG:

• If streptococcal toxic shock syndrome (STSS)
• Dose: 1-2 g/kg as single dose
• Neutralises circulating toxins
• Evidence: small studies suggest benefit in STSS [16]

Oral Step-Down Therapy

Once afebrile for 24-48 hours and clinically improved:

Switch to oral antibiotics to complete 7-10 days total:

Breastfeeding Considerations:

• Co-amoxiclav, clindamycin, cephalosporins: safe
• Metronidazole: avoid if possible (or discard milk for 12-24h after doses)
• Gentamicin: minimal excretion into milk, safe
• Doxycycline: AVOID (tetracyclines contraindicated in breastfeeding)

Supportive Management

Monitoring Response to Treatment

Expected Response:

• Fever should settle within 48-72 hours
• Clinical improvement (reduced pain, improved wellbeing) within 24-48 hours
• Normalisation of inflammatory markers (CRP falls) over 3-5 days

Monitoring Parameters:

• Vital signs (4-hourly minimum, more frequent if septic)
• Temperature chart (expect defervescence by 48-72h)
• Clinical symptoms (pain, lochia, wellbeing)
• FBC, CRP (repeat at 48-72h)
• Urine output (if catheterised)

Failure to Respond (No Improvement by 48-72h)

If patient remains febrile or clinically unwell after 48-72 hours of appropriate IV antibiotics:

Reassess Diagnosis

Is it definitely endometritis?

• Review "5 T's" differential diagnosis
• Consider:
  • Wound infection
  • Pelvic abscess
  • Retained products of conception
  • Septic pelvic thrombophlebitis
  • Drug fever

Investigate for Complications

Imaging:

• Pelvic ultrasound: Assess for retained products of conception, pelvic abscess, intrauterine collection
• CT pelvis (contrast): If USS non-diagnostic or concern for abscess, necrotising fasciitis, septic thrombophlebitis

Microbiology review:

• Review culture results (blood, HVS)
• Resistant organisms? (MRSA, ESBL-producing Gram-negatives, Enterococcus)
• Atypical organisms? (Mycoplasma, Ureaplasma)

Repeat blood cultures

Modify Antibiotic Therapy

Broaden coverage:

• Switch to piperacillin-tazobactam 4.5g IV q8h (broader spectrum, covers Pseudomonas)
• Add ampicillin if not already given (Enterococcal coverage)
• Consider meropenem if severe or resistant organisms suspected
• Liaise with microbiology/infectious diseases

If MRSA suspected:

• Add vancomycin or linezolid

Surgical Intervention

Indications for surgery:

1. Retained products of conception

   • Surgical evacuation (suction curettage under USS guidance)
   • Antibiotics alone insufficient
   • Send products for histology and microbiology

2. Pelvic abscess

   • Drainage (percutaneous under USS/CT guidance or surgical)
   • Antibiotics alone often insufficient for large abscesses (> 5 cm)

3. Necrotising fasciitis (SURGICAL EMERGENCY)

   • Immediate extensive surgical debridement
   • May require multiple operations
   • High mortality if delayed
   • Critical care support

4. Uterine necrosis/perforation

   • Rare
   • May require laparotomy ± hysterectomy

Septic Pelvic Thrombophlebitis

Diagnosis of exclusion: persistent spiking fevers despite appropriate antibiotics and no other identified source

Clinical features:

• "Picket-fence" fever pattern (spiking)
• Otherwise well between spikes
• Pelvic or lower limb DVT may be present

Investigations:

• CT/MRI pelvis: may show thrombus in ovarian veins or pelvic veins
• D-dimer elevated (but also elevated postpartum anyway)

Management:

• Anticoagulation (therapeutic LMWH or heparin)
• Continue antibiotics
• Empirical heparin trial: if fever resolves within 48-72h, supports diagnosis

Algorithm: Management of Postpartum Endometritis

┌─────────────────────────────────────────────────────────────────────┐
│                POSTPARTUM FEVER + UTERINE TENDERNESS                │
│                   Suspect ENDOMETRITIS                              │
└────────────────────────────┬────────────────────────────────────────┘
                             │
                             ▼
                    ┌────────────────────┐
                    │  ASSESS FOR SEPSIS │
                    │   (ABCDE, MEOWS)   │
                    └────────┬───────────┘
                             │
               ┌─────────────┴──────────────┐
               │                            │
         SEPSIS PRESENT              NO SEPSIS / MILD
               │                            │
               ▼                            ▼
      ┌────────────────────┐      ┌─────────────────────┐
      │   SEPSIS 6 BUNDLE  │      │  INVESTIGATIONS:    │
      │   (within 1 hour)  │      │  - Septic screen    │
      │                    │      │  - Blood cultures   │
      │ Give:              │      │  - FBC, CRP, U&Es   │
      │ • O₂               │      │  - Lactate          │
      │ • IV fluids        │      │  - HVS              │
      │ • IV antibiotics   │      │  - Pelvic USS       │
      │                    │      └──────────┬──────────┘
      │ Take:              │                 │
      │ • Blood cultures   │                 │
      │ • Lactate          │                 ▼
      │ • Monitor UO       │      ┌─────────────────────┐
      │                    │      │  START ANTIBIOTICS  │
      │ ESCALATE TO HDU/ICU│      │                     │
      └─────────┬──────────┘      │  CLINDAMYCIN 900mg  │
                │                 │  IV q8h             │
                │                 │  +                  │
                └────────────────►│  GENTAMICIN 5mg/kg  │
                                  │  IV q24h            │
                                  └──────────┬──────────┘
                                             │
                                             ▼
                              ┌──────────────────────────────┐
                              │  SUPPORTIVE MANAGEMENT:      │
                              │  • IV fluids                 │
                              │  • Analgesia (paracetamol,   │
                              │    ibuprofen)                │
                              │  • VTE prophylaxis (LMWH)    │
                              │  • Monitor vital signs       │
                              └─────────────┬────────────────┘
                                            │
                                            ▼
                              ┌──────────────────────────────┐
                              │  REASSESS AT 48-72 HOURS     │
                              └─────────────┬────────────────┘
                                            │
                          ┌─────────────────┴──────────────────┐
                          │                                    │
                    IMPROVED                            NO IMPROVEMENT
                          │                                    │
                          ▼                                    ▼
              ┌────────────────────┐           ┌───────────────────────────┐
              │ Continue IV until  │           │  INVESTIGATE:             │
              │ afebrile 24-48h    │           │  • Pelvic USS (RPOC?)     │
              │                    │           │  • CT pelvis (abscess?)   │
              │ Switch to ORAL:    │           │  • Review cultures        │
              │ Co-amoxiclav       │           │  • Repeat blood cultures  │
              │ 875/125mg PO q12h  │           │                           │
              │                    │           │  REASSESS DIAGNOSIS:      │
              │ Complete 7-10 days │           │  • Wound infection?       │
              │ total              │           │  • Pelvic abscess?        │
              └──────────┬─────────┘           │  • Septic thrombophlebitis│
                         │                     │  • Resistant organisms?   │
                         ▼                     └─────────────┬─────────────┘
              ┌────────────────────┐                         │
              │  DISCHARGE         │                         ▼
              │                    │           ┌──────────────────────────┐
              │  • Complete oral   │           │  MODIFY TREATMENT:       │
              │    antibiotics     │           │  • Broaden antibiotics   │
              │  • GP follow-up    │           │    (pip-tazo, meropenem) │
              │  • Red flag advice │           │  • Add ampicillin        │
              │  • Contraception   │           │  • Microbiology advice   │
              │  • Psychological   │           │                          │
              │    support         │           │  SURGICAL INTERVENTION:  │
              └────────────────────┘           │  • Evacuate RPOC         │
                                               │  • Drain abscess         │
                                               │  • Debride if necrotising│
                                               │                          │
                                               │  CONSIDER:               │
                                               │  • Anticoagulation       │
                                               │    (if septic thrombosis)│
                                               │  • ICU referral          │
                                               └──────────────────────────┘

Exam Detail: ### MRCOG Written/Viva: Management Scenarios

Scenario 1: "A 32-year-old woman, day 3 post-emergency caesarean, has fever 39.1°C, HR 118, BP 102/68, uterine tenderness. How do you manage her?"

Model Answer:

"This is likely postpartum endometritis given the timing, mode of delivery, and clinical findings. I would manage systematically:

Immediate Assessment (ABCDE):

• Assess for sepsis using MEOWS - she has fever and tachycardia, borderline BP
• Check lactate, consciousness, urine output

If Sepsis Suspected (MEOWS triggers or lactate > 2):

• Sepsis 6 within 1 hour:
  • "Give: High-flow O₂, IV fluid bolus 500mL, IV antibiotics"
  • "Take: Blood cultures, lactate, monitor urine output (catheterise)"
• Escalate to senior obstetrician and critical care

Investigations:

• Septic screen: FBC, CRP, U&Es, LFTs, clotting, lactate
• Blood cultures (2 sets, before antibiotics if possible)
• High vaginal swab
• MSU
• Pelvic ultrasound (assess for RPOC, abscess)

Antibiotic Treatment:

• First-line: Clindamycin 900mg IV q8h + Gentamicin 5mg/kg IV q24h
• This covers polymicrobial infection (Gram-positive, Gram-negative, anaerobes)

Supportive Care:

• IV fluids, analgesia (paracetamol, ibuprofen)
• VTE prophylaxis (LMWH)
• Monitor vital signs 4-hourly (or more frequently)

Monitoring:

• Expect clinical improvement within 24-48h, defervescence by 48-72h
• If no improvement → investigate for complications (RPOC, abscess, resistant organisms)

Step-down:

• Once afebrile 24-48h → switch to oral co-amoxiclav
• Complete 7-10 days total
• Discharge with GP follow-up, red flag advice, contraception counselling"

---

Scenario 2: "A patient with endometritis on clindamycin + gentamicin remains febrile on day 5 of treatment. What are your next steps?"

Model Answer:

"Failure to respond after 48-72 hours requires systematic reassessment:

1. Reassess Diagnosis:

• Is it definitely endometritis or could it be another cause of postpartum fever?
• Review the '5 T's': wound infection, mastitis, DVT, UTI

2. Investigate for Complications:

• Pelvic ultrasound: Retained products of conception? Pelvic abscess? Intrauterine collection?
• CT pelvis if USS non-diagnostic: better for abscess, septic thrombophlebitis, necrotising fasciitis
• Repeat blood cultures
• Review microbiology results: resistant organisms? Culture sensitivities?

3. Modify Antibiotics:

• Broaden coverage: switch to piperacillin-tazobactam or meropenem
• Add ampicillin for Enterococcal coverage
• If MRSA suspected: add vancomycin
• Involve microbiology/infectious diseases

4. Surgical Intervention:

• RPOC: evacuate uterus (suction curettage under USS guidance)
• Abscess: drainage (percutaneous or surgical)
• Necrotising fasciitis: EMERGENCY - immediate extensive debridement

5. Consider Septic Pelvic Thrombophlebitis:

• Diagnosis of exclusion (spiking fevers, no other source)
• CT/MRI may show ovarian/pelvic vein thrombosis
• Trial of therapeutic anticoagulation

6. Escalate:

• Senior obstetric and critical care team involvement
• Consider transfer to tertiary centre if complex"

---

8. Prevention

Prophylactic Antibiotics at Caesarean Section

Antibiotic prophylaxis at the time of caesarean section is one of the most effective interventions in obstetrics, reducing endometritis rates by 60-70% and wound infections by ~50%. [9,19]

Evidence Base

Cochrane Systematic Review (2014): Pooled data from 95 RCTs involving > 15,000 women:

• Endometritis reduced by 60-70% (RR 0.38, 95% CI 0.34-0.42)
• Wound infection reduced by ~50% (RR 0.61, 95% CI 0.52-0.71)
• Serious maternal infection reduced by 69% (RR 0.31, 95% CI 0.19-0.48)
• Number needed to treat (NNT) = 20 to prevent one case of endometritis
• Cost-effective: saves healthcare costs through reduced infections [9]

Recommended Regimen

Additional Measure for Emergency Caesarean in Labour:

• Some guidelines recommend adding azithromycin 500mg IV to standard cefazolin for emergency CS in labour (covers atypical organisms, additional anaerobic coverage)
• Evidence: reduces endometritis further in high-risk women [20]

Extended Prophylaxis

Single dose is standard. Routine extended prophylaxis (continuing antibiotics postoperatively) is NOT recommended as:

• No additional benefit over single dose [19]
• Increased antibiotic resistance
• Increased cost
• Increased side effects

Exception: May consider extended prophylaxis in very high-risk patients:

• Morbid obesity (BMI > 40)
• Immunosuppression
• Prolonged surgery (> 3 hours)
• Heavy contamination

Vaginal Preparation

Vaginal cleansing with antiseptic (povidone-iodine, chlorhexidine) prior to caesarean reduces endometritis by ~40%. [21]

Technique:

• Apply antiseptic (povidone-iodine 10% or chlorhexidine 0.2%) to vagina immediately before CS
• Wipe vaginal walls and cervix
• Simple, low-cost intervention
• Cochrane meta-analysis: reduces endometritis (RR 0.41, 95% CI 0.29-0.58) [21]

Other Preventive Strategies

Enhanced Recovery After Surgery (ERAS) Protocols

ERAS pathways for caesarean section include infection prevention bundles:

• Preoperative antibiotic prophylaxis (pre-incision)
• Vaginal preparation
• Optimal glycaemic control (diabetics)
• Normothermia (hypothermia ↑ infection risk)
• Early mobilisation
• Early removal of catheter (reduces UTI)

These protocols reduce overall morbidity including infectious complications. [23]

---

9. Complications

Early Complications (Days-Weeks)

Sepsis and Septic Shock

Most serious acute complication of endometritis.

Progression:

• Infection → Systemic Inflammatory Response (SIRS) → Sepsis → Severe Sepsis (organ dysfunction) → Septic Shock (refractory hypotension)

Clinical Features:

• Hypotension (SBP less than 90 mmHg despite fluids)
• Tachycardia > 130 bpm
• Lactate > 2 mmol/L (> 4 mmol/L = severe)
• Altered consciousness
• Oliguria (less than 0.5 mL/kg/h)
• Mottled skin, cold peripheries

Management:

• Immediate resuscitation (Sepsis 6)
• Intensive care support (vasopressors, organ support)
• Broad-spectrum antibiotics
• Source control (drainage, surgery)

Mortality: 5-10% in high-income settings; higher in low-resource settings [1,2]

Pelvic Abscess

Occurs in 1-3% of endometritis cases, typically when treatment delayed or infection severe. [10]

Sites:

• Tubo-ovarian abscess
• Pouch of Douglas collection
• Broad ligament abscess
• Parametrial abscess

Clinical Features:

• Persistent fever despite antibiotics
• Severe pelvic pain
• Adnexal mass on examination
• Pelvic tenderness

Diagnosis:

• Pelvic ultrasound: complex cystic mass, thick-walled
• CT pelvis: rim-enhancing collection

Management:

• Antibiotics alone if small (less than 5 cm) and patient stable
• Drainage if large (> 5 cm) or not responding:
  • Percutaneous drainage (USS or CT-guided)
  • Surgical drainage (laparoscopy or laparotomy)
• May require prolonged antibiotics (3-6 weeks)

Complications of abscess:

• Rupture → peritonitis
• Bowel/bladder fistula (rare)

Peritonitis

Spread of infection beyond uterus → generalised abdominal sepsis.

Clinical Features:

• Severe abdominal pain
• Guarding, rigidity, rebound tenderness
• Absent bowel sounds
• Septic, unwell

Management:

• Aggressive resuscitation
• Broad-spectrum antibiotics
• Laparotomy (diagnostic and therapeutic)
• Source control (drainage, washout, ? hysterectomy)

Septic Pelvic Thrombophlebitis (SPT)

Thrombosis of pelvic veins (ovarian veins, internal iliac veins) with septic emboli.

Incidence: less than 1% of postpartum infections [24]

Clinical Features:

• Persistent "spiking fevers" (picket-fence pattern) despite appropriate antibiotics
• Otherwise relatively well between spikes
• May have pelvic or leg pain (DVT)

Diagnosis:

• Diagnosis of exclusion (other causes ruled out)
• CT/MRI pelvis: may show thrombus in ovarian or pelvic veins (but often normal)
• Empirical trial of anticoagulation: fever resolves within 48-72h → supports diagnosis

Management:

• Therapeutic anticoagulation (LMWH or heparin) for 3-6 months
• Continue antibiotics
• Monitor for septic pulmonary emboli (rare)

Necrotising Fasciitis

Rare but LIFE-THREATENING surgical emergency - rapidly progressive soft tissue infection with necrosis. [25]

Organisms:

• Polymicrobial (Type I): mix of aerobes and anaerobes
• Group A Streptococcus (Type II): monomicrobial, highly virulent

Clinical Features:

• Pain out of proportion to clinical findings (hallmark)
• Erythema, swelling, induration
• Skin changes: bronze discolouration, bullae, crepitus (gas in tissues)
• Rapidly progressive (hours)
• Severe systemic toxicity, septic shock

LRINEC Score (Laboratory Risk Indicator for Necrotising Fasciitis):

• Score ≥6 suggests necrotising fasciitis
• Components: CRP, WCC, Hb, Na, Creatinine, Glucose

Diagnosis:

• Clinical suspicion is key (do not wait for imaging)
• CT: gas in soft tissues, fascial thickening
• Surgical exploration is diagnostic and therapeutic

Management:

• EMERGENCY - immediate surgical debridement (extensive, may require multiple operations)
• Broad-spectrum antibiotics (meropenem + clindamycin + linezolid)
• Clindamycin suppresses toxin production (critical in GAS)
• Intensive care support
• May require hysterectomy if uterine involvement
• High mortality (20-40%) even with treatment [25]

Intermediate/Late Complications (Weeks-Months)

Chronic Pelvic Pain

• Adhesions from pelvic inflammation
• Pelvic congestion
• Affects quality of life
• May require chronic pain management

Tubal Damage and Infertility

Pelvic infection can damage fallopian tubes → tubal factor infertility, ectopic pregnancy risk.

• Endometritis extending to parametrium → salpingitis
• Inflammatory damage → tubal scarring, adhesions
• Risk of future ectopic pregnancy (2-3 fold increased)
• Risk of secondary infertility

Counselling:

• Advise about increased ectopic risk in future pregnancies
• Early pregnancy scan in subsequent pregnancies
• Fertility assessment if difficulty conceiving

Asherman Syndrome (Intrauterine Adhesions)

Scarring of endometrial cavity following severe endometritis, especially if surgical evacuation performed.

Clinical Features:

• Amenorrhoea or hypomenorrhoea
• Recurrent pregnancy loss
• Infertility
• Cyclical pelvic pain (if partial obstruction)

Diagnosis:

• Hysteroscopy (gold standard)
• Hysterosalpingography (filling defects)
• USS: thin endometrium, may see adhesions

Management:

• Hysteroscopic adhesiolysis
• Postoperative oestrogen
• Intrauterine balloon/IUD to prevent re-adhesion

Psychological Sequelae

• Postnatal depression (hospitalisation, severe illness are risk factors)
• Post-traumatic stress disorder (PTSD) following severe sepsis, ICU admission
• Anxiety about future pregnancies
• Bonding difficulties (separation from baby during illness)

Management:

• Psychological support, counselling
• Debriefing after severe illness
• Screen for postnatal depression
• Involve specialist perinatal mental health services if needed

Maternal Mortality

Postpartum sepsis (including endometritis progressing to severe sepsis) remains a leading cause of direct maternal death in the UK and globally. [1,17]

MBRRACE-UK data (Confidential Enquiries into Maternal Deaths):

• Sepsis accounts for ~10-15% of direct maternal deaths in UK
• Case fatality rate for severe sepsis: 5-10%
• Group A Streptococcus disproportionately represented in maternal deaths
• Common themes in maternal deaths from sepsis:
  • Delayed recognition
  • Failure to escalate
  • Inadequate initial resuscitation
  • Underestimation of severity

Key Lessons:

• "Think Sepsis" in any unwell postpartum woman
• Act Fast - Sepsis 6 within 1 hour
• Escalate Early - senior and critical care involvement
• GAS is particularly dangerous - high index of suspicion, aggressive treatment

---

10. Prognosis and Outcomes

With Prompt Appropriate Treatment

Excellent prognosis in uncomplicated cases:

• Clinical improvement: Expected within 24-48 hours
• Defervescence: Fever settles within 48-72 hours in 90% of cases [7,8]
• Cure rate: > 90-95% with clindamycin + gentamicin [7]
• Hospital stay: Typically 4-7 days (until afebrile 24-48h, then discharge on oral antibiotics)
• Complete recovery: Most women fully recover without long-term sequelae
• Breastfeeding: Can continue throughout treatment (most antibiotics compatible)
• Future fertility: Not affected in uncomplicated cases

Delayed or Inadequate Treatment

Worse outcomes if treatment delayed or inadequate:

• Progression to severe sepsis / septic shock: 5-10% if treatment delayed
• Complications: Pelvic abscess (1-3%), peritonitis, septic thrombophlebitis
• Need for surgical intervention: Evacuation of RPOC, drainage of abscess, rarely hysterectomy
• ICU admission: 1-2% in severe cases
• Mortality: less than 1% in high-income settings with prompt treatment; 5-10% if severe sepsis; Up to 50-60% if GAS toxic shock and delayed treatment [6,16,17]
• Long-term sequelae: Chronic pelvic pain, tubal damage, secondary infertility, psychological trauma

Factors Associated with Poorer Prognosis

Subsequent Pregnancies

Following uncomplicated endometritis:

• No increased risk of recurrence in subsequent pregnancies (if vaginal delivery)
• Increased risk if repeat caesarean (same underlying risk factor)
• Antibiotic prophylaxis at caesarean section essential

Counselling:

• Explain importance of prophylactic antibiotics at future caesarean
• Discuss mode of delivery (VBAC vs repeat CS) - separate considerations
• Advise early presentation if postpartum fever in future
• Reassure about fertility (not affected in uncomplicated cases)

---

11. Key Guidelines and Evidence

Guidelines

Key Evidence

Landmark Studies

1. Cochrane Review: Antibiotic Prophylaxis for Caesarean Section (2014) [9]

• 95 RCTs, > 15,000 women
• Findings: Prophylactic antibiotics reduce endometritis by 60-70%, wound infection by 50%, serious infection by 69%
• NNT = 20 to prevent one endometritis
• Conclusion: Routine prophylaxis at CS highly effective and cost-effective

2. Timing of Prophylactic Antibiotics: Pre-incision vs Post-cord Clamping (Multiple RCTs, Meta-analyses) [20]

• Findings: Pre-incision superior to post-cord clamping for reducing endometritis and wound infection
• Does NOT increase neonatal sepsis investigations or treatment
• Conclusion: Give antibiotics before skin incision (historical practice of post-cord clamping now obsolete)

3. ACOG Guideline Change (2018): Adding Azithromycin for Emergency CS [20]

• RCT (Tita et al., NEJM 2016): Adding azithromycin 500mg IV to standard cefazolin for emergency CS in labour
• Findings: Reduced composite maternal infection (endometritis + wound infection) by 50% (adjusted OR 0.46)
• Conclusion: Consider adding azithromycin for high-risk emergency CS in labour

4. Vaginal Preparation with Antiseptic Before CS [21]

• Cochrane review: 17 RCTs
• Findings: Vaginal cleansing with povidone-iodine or chlorhexidine reduces endometritis by ~60% (RR 0.41)
• Simple, low-cost intervention
• Conclusion: Routine vaginal preparation recommended

5. Clindamycin + Gentamicin for Treatment of Endometritis [7,8]

• Multiple RCTs establishing clindamycin + gentamicin as gold standard
• Cure rates: 90-95% in uncomplicated endometritis
• Conclusion: First-line regimen

6. MBRRACE-UK Confidential Enquiries (Annual Reports) [17]

• Ongoing surveillance of maternal deaths in UK
• Findings: Sepsis accounts for ~10-15% of direct maternal deaths; GAS disproportionately represented; themes include delayed recognition and inadequate initial treatment
• Conclusion: Emphasises importance of early recognition, Sepsis 6, escalation

---

12. Examination Focus (MRCOG / Postgraduate)

High-Yield Viva Topics

Viva Question 1: Risk Factors

Examiner: "What is the single most important risk factor for postpartum endometritis, and why?"

Model Answer:

"The single most important risk factor is caesarean section, which increases the risk of postpartum endometritis 10-20 fold compared to vaginal delivery.

The mechanism is multifactorial:

1. Breach of natural barriers: Direct incision through the uterine wall bypasses the cervical barrier and introduces organisms from the vagina and skin into the normally sterile uterine cavity and peritoneum
2. Surgical trauma: Devitalised tissue, haematoma, and foreign material (sutures) provide a nidus for bacterial growth
3. Contamination: Despite aseptic technique, vaginal organisms can contaminate the operative field
4. Associated risk factors: Emergency CS in labour often combines prolonged rupture of membranes, prolonged labour, and multiple vaginal examinations, compounding the risk

Emergency caesarean in labour carries the highest risk (15-25% without prophylaxis), while elective pre-labour caesarean has lower but still significantly elevated risk compared to vaginal delivery.

This is why prophylactic antibiotics at caesarean section are so important - they reduce endometritis rates by 60-70% and represent one of the most cost-effective interventions in obstetrics."

---

Viva Question 2: Microbiology

Examiner: "Describe the typical microbiology of postpartum endometritis."

Model Answer:

"Postpartum endometritis is typically a polymicrobial infection in 60-70% of cases, involving a mix of organisms ascending from the lower genital tract.

Common organisms include:

Gram-positive cocci:

• Group A Streptococcus (S. pyogenes) - highly virulent, can cause fulminant sepsis
• Group B Streptococcus (S. agalactiae) - common vaginal coloniser
• Enterococcus - note: resistant to cephalosporins and clindamycin
• Staphylococcus aureus - including MRSA

Gram-negative bacilli:

• E. coli - the most common aerobic organism
• Klebsiella, Proteus

Anaerobes:

• Bacteroides fragilis - the most common anaerobe; produces β-lactamase
• Prevotella, Peptostreptococcus - cause foul-smelling discharge

Atypical:

• Mycoplasma hominis, Ureaplasma - cell wall-deficient, resistant to β-lactams

Special mention: Group A Streptococcus

GAS deserves particular emphasis because it can cause rapidly progressive, life-threatening sepsis with streptococcal toxic shock syndrome and necrotising fasciitis. It typically presents early (less than 24-48h postpartum) with severe systemic toxicity. Treatment requires high-dose penicillin plus clindamycin (to suppress toxin production), and has high mortality if diagnosis is delayed.

The polymicrobial nature of endometritis is why we use broad-spectrum combination therapy - clindamycin + gentamicin - to cover Gram-positives, Gram-negatives, and anaerobes."

---

Viva Question 3: Management of Non-Responder

Examiner: "A patient with endometritis on clindamycin and gentamicin remains febrile and unwell on day 4. How do you proceed?"

Model Answer:

"Failure to respond to appropriate antibiotics within 48-72 hours requires systematic reassessment. I would approach this as follows:

1. Reassess the diagnosis

• Is it definitely endometritis or could it be another cause of postpartum fever?
• Review the '5 T's': Temperature (endometritis), Thrombophlebitis, Trauma (wound infection), Tissue (RPOC), Teat (mastitis)

2. Clinical re-examination

• Full ABCDE assessment
• Signs of sepsis worsening?
• Abdominal examination: peritonism? Wound infection?
• Vaginal examination: lochia, uterine tenderness

3. Investigate for complications

Imaging:

• Pelvic ultrasound: Assess for retained products of conception (heterogeneous endometrial material, thickened endometrium, vascularity on Doppler), pelvic abscess, intrauterine collection
• CT pelvis with contrast if USS non-diagnostic: better for identifying abscess, necrotising fasciitis (gas in tissues), septic pelvic thrombophlebitis (ovarian vein thrombus)

Microbiology:

• Review culture results (blood, HVS)
• Repeat blood cultures
• Are organisms resistant? MRSA, ESBL-producing Gram-negatives, Enterococcus?

Blood tests:

• Repeat FBC, CRP (trending up vs down?), U&Es, lactate
• Clotting if severe

4. Modify antibiotic therapy

• Broaden coverage: Switch to piperacillin-tazobactam 4.5g IV q8h or meropenem 1g IV q8h
• Add ampicillin 2g IV q6h for Enterococcal coverage (clindamycin doesn't cover Enterococcus)
• If MRSA suspected: add vancomycin or linezolid
• Involve microbiology/infectious diseases for advice

5. Surgical intervention

If imaging identifies:

• Retained products: surgical evacuation (suction curettage under USS guidance); send products for histology and microbiology
• Pelvic abscess: drainage required (percutaneous under USS/CT guidance, or surgical)
• Necrotising fasciitis: SURGICAL EMERGENCY - immediate extensive debridement, may require multiple operations, critical care

6. Consider septic pelvic thrombophlebitis

• Diagnosis of exclusion (persistent spiking fevers, no other source, imaging may show pelvic vein thrombus)
• Empirical trial of therapeutic anticoagulation (LMWH)
• If fever resolves within 48-72h → supports diagnosis

7. Escalate

• Senior obstetric team
• Critical care involvement if haemodynamically unstable
• Consider transfer to tertiary centre if complex

The key is not to persist with failing treatment - active investigation and modification of the management plan is essential."

---

Viva Question 4: Prevention

Examiner: "What is the evidence for antibiotic prophylaxis at caesarean section?"

Model Answer:

"There is very strong Level I evidence from a Cochrane systematic review supporting routine antibiotic prophylaxis at caesarean section.

Cochrane Review (2014):

• Pooled 95 RCTs involving over 15,000 women
• Key findings:
  • Endometritis reduced by 60-70% (RR 0.38)
  • Wound infection reduced by ~50% (RR 0.61)
  • Serious maternal infection reduced by 69% (RR 0.31)
  • Number needed to treat = 20 to prevent one case of endometritis

This makes prophylactic antibiotics at caesarean section one of the most effective and cost-effective interventions in obstetric practice.

Recommended regimen:

• Agent: Cefazolin (1st generation cephalosporin) 2g IV single dose (3g if BMI > 35 or weight > 100kg)
• Timing: Before skin incision (within 60 minutes)
  • Previously given after cord clamping to avoid theoretical neonatal exposure
  • Evidence now shows pre-incision is superior and does NOT increase neonatal sepsis investigations
• Alternative: Co-amoxiclav 1.2g IV
• Penicillin allergy: Clindamycin 600-900mg + gentamicin 5mg/kg IV

Additional measures:

• Vaginal preparation with antiseptic (povidone-iodine, chlorhexidine) reduces endometritis by further ~40% (Cochrane review 2017)
• Azithromycin 500mg IV added to standard prophylaxis for emergency CS in labour reduces infection by additional ~50% (ACOG 2018, following RCT by Tita et al. in NEJM 2016)

Single dose is standard; routine extended prophylaxis postoperatively is NOT recommended (no additional benefit, increases resistance and cost).

The evidence is so strong that prophylactic antibiotics at CS are now mandatory standard of care worldwide."

---

OSCE Stations: Common Scenarios

Station 1: Breaking Bad News / Explanation

Scenario: Explain postpartum endometritis diagnosis to a woman on day 3 post-caesarean with fever and uterine tenderness.

Key Points to Cover:

• Warm, empathetic introduction
• Explain diagnosis in layperson terms ("infection of the womb lining")
• Link to caesarean ("more common after CS")
• Reassure that it's treatable ("antibiotics through a drip")
• Explain treatment plan (IV antibiotics, expected response in 2-3 days)
• Discuss need for hospitalisation
• Reassure about breastfeeding (can continue)
• Red flag advice (if symptoms worsen)
• Opportunity for questions

---

Station 2: Emergency Management

Scenario: Manage a postpartum woman with suspected sepsis secondary to endometritis.

Key Actions:

• A-E assessment systematically
• Recognise sepsis (fever, tachycardia, hypotension, lactate)
• Call for help (senior obstetrician, anaesthetist, critical care)
• Initiate Sepsis 6 within 1 hour:
  • "Give: Oxygen, IV fluids, IV antibiotics"
  • "Take: Blood cultures, lactate, monitor urine output"
• Specific investigations: Septic screen (FBC, CRP, cultures, USS)
• Definitive treatment: Clindamycin + gentamicin IV
• Monitoring: Continuous, escalate if deteriorating
• Documentation: Clear, timestamped
• Communicate: With team, with patient/family

---

13. Patient / Layperson Explanation

What is Postpartum Endometritis?

Postpartum endometritis is an infection of the lining of the womb (called the endometrium) that happens after you've had your baby. It's one of the more common infections that can occur after giving birth, especially after a caesarean section (C-section).

Why Does It Happen?

After delivery, the inside of your womb is like an open wound where the placenta was attached. Normally, your body heals this naturally, but sometimes bacteria (germs) from the vagina can get into the womb and cause an infection.

You're more likely to get this infection if:

• You had a caesarean section (this is the biggest risk factor)
• Your waters broke a long time before the baby was born
• You had a long labour
• You had lots of internal examinations during labour
• The placenta or part of it was left behind

What Are the Symptoms?

The main symptoms are:

• High temperature (fever) - usually starting 2-5 days after giving birth
• Tummy pain - especially when the lower part of your tummy is pressed
• Smelly discharge from the vagina (the lochia, or bleeding after birth, smells unpleasant)
• Feeling generally unwell - tired, achy, like you have the flu

Is It Serious?

It can be serious if not treated, but with prompt treatment, most women make a full recovery.

If left untreated, the infection can spread and make you very unwell (a condition called sepsis), which can be life-threatening. That's why it's important to get medical help quickly if you have these symptoms.

How Is It Treated?

You'll need antibiotics (medicines that kill the bacteria causing the infection). These are given through a drip into your vein (IV antibiotics) in hospital, because they work faster and more effectively than tablets.

The usual treatment involves:

• Staying in hospital for a few days
• Antibiotics through a drip until your temperature has been normal for 1-2 days
• Then switching to antibiotic tablets to take at home for about a week
• Painkillers to help with discomfort

Most women start to feel better within 24-48 hours of starting treatment, and the fever usually goes away within 2-3 days.

Can I Breastfeed?

Yes! You can continue to breastfeed while you're being treated. The antibiotics used are safe for your baby. In fact, continuing to breastfeed is good for both you and your baby.

Will I Need Surgery?

Usually not. Most women get better with antibiotics alone. However, if a piece of placenta was left behind in your womb, you might need a small procedure to remove it. This is done under anaesthetic and is similar to a D&C.

How Can It Be Prevented?

The best way to prevent this infection is to give antibiotics at the time of a caesarean section. This is now routine practice - you'll be given an antibiotic through your drip just before the operation starts. This reduces the risk of infection by more than half.

What Should I Watch Out For at Home?

After going home, contact your doctor or midwife urgently if you develop:

• High temperature (fever)
• Shivering or shaking
• Severe tummy pain
• Smelly vaginal discharge
• Feeling very unwell

Will It Affect Future Pregnancies?

In most cases, no. Once the infection is treated and cleared, it shouldn't affect your ability to have more babies in the future. If you have another caesarean in a future pregnancy, you'll again receive preventive antibiotics.

Key Message

Postpartum endometritis is a treatable infection. The important thing is to recognise the symptoms early and get medical help quickly. With antibiotics, almost all women make a full recovery and can continue to care for and feed their babies.

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