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Caesarean Section in Obstructed Labour - DNB Answer (April 2023) [2+3+5 Marks]

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WHY OBSTRUCTED LABOUR MAKES CS HIGH-RISK

• Lower uterine segment is thin, oedematous, and friable
• Bladder is pulled up and adherent to the lower segment
• Fetal head is deeply impacted in the pelvis
• Bandl's pathological retraction ring may be present
• Tissues are infected, hypoxic, and friable after prolonged labour

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a) COMPLICATIONS OF CS IN OBSTRUCTED LABOUR (2 Marks)

INTRAOPERATIVE COMPLICATIONS

POSTOPERATIVE COMPLICATIONS

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b) PREVENTIVE MEASURES (3 Marks)

PRE-OPERATIVE PREVENTION

• IV access x2; send blood for CBC, group & crossmatch
• Correct hypovolaemia: Ringer's Lactate/Normal Saline, blood transfusion if Hb <8 g/dL
• Correct electrolyte imbalance (dehydration is universal in obstructed labour)
• Nasogastric tube + antacid (0.3M sodium citrate 30 mL) to reduce aspiration risk

• Ensure Foley catheter is draining freely before starting
• Empty bladder completely - reduces bladder injury risk

• Cefazolin 2g IV at time of skin incision (ACOG/RCOG recommendation)
• OR if allergic: Clindamycin 600mg + Gentamicin 1.5mg/kg IV
• Azithromycin 500mg IV added for non-elective CS (Tita et al. - reduces endometritis significantly)
• Vaginal cleansing with 10% povidone-iodine before CS (Cochrane review, 2635 women: reduces SSI)

• Experienced anaesthetist mandatory
• Spinal anaesthesia preferred (avoids failed intubation risk)
• If GA needed: rapid sequence induction (RSI) with cricoid pressure
• Pre-oxygenation for 3-5 min before induction
• Left lateral tilt (15°) to avoid aortocaval compression

• Senior/experienced surgeon to perform the CS
• Do not delegate to a junior - obstructed labour CS is high risk

• If Bandl's ring identified: give IV/sublingual GTN (glyceryl trinitrate) OR terbutaline SC for uterine relaxation before/during extraction
• Tocolysis allows safe extraction without rupture (Queensland Clinical Guidelines 2025)

INTRAOPERATIVE PREVENTION

• Pfannenstiel incision is standard
• If previous scars/adhesions: Pfannenstiel with care OR midline (better exposure)
• Uterine incision: low transverse (Joel-Cohen modification preferred - less blood loss)

• Push bladder down carefully with a wet swab - do NOT cut hastily
• Identify bladder boundaries before making uterine incision
• Keep bladder retractor in position throughout

HEAD DEEPLY IMPACTED - APPROACH:
                    |
        ┌───────────┴───────────┐
   PUSH technique           PULL technique
(Assistant pushes head         (Patwardhan method,
 up from below vaginally)    Classical incision if needed)
        |                           |
  Wrigley's forceps          Reverse breech extraction
  after disimpaction          (feet first via fundal 
                               pressure / incision)

• Use vacuum extractor or Wrigley's forceps gently after disimpacting the head
• Patwardhan's technique: deliver shoulders first, then head (for deeply engaged head)
• Consider classical (vertical) uterine incision if lower segment is poorly formed or Bandl's ring present
• AVOID fundal pressure without proper disimpaction - can cause uterine rupture

• Active management of third stage: Oxytocin 10 IU IV immediately after delivery
• Uterine massage
• Check for lateral extensions of incision before closing

• TED stockings intraoperatively
• LMWH (Enoxaparin 40mg SC) from 6-12 hours post-op (RCOG guidelines)
• Early mobilisation

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c) MANAGEMENT OF COMPLICATIONS (5 Marks)

1. POSTPARTUM HAEMORRHAGE (PPH)

STEP 1: Bimanual uterine compression + Oxytocin 10-20 IU IV infusion
         +Ergometrine 0.5mg IM (avoid in hypertension)
         +Misoprostol 800 mcg sublingual/rectal
         +Carboprost 0.25mg IM every 15 min (max 8 doses)
         +Tranexamic acid (TXA) 1g IV within 3 hours of PPH onset
         +IV fluids / Blood transfusion
              ↓
STEP 2: Surgical - Uterine compression sutures
         B-Lynch suture / Hayman suture / Cho sutures (squeezing sutures)
              ↓
STEP 3: Uterine artery ligation (O'Leary stitch)
         Internal iliac artery ligation
              ↓
STEP 4: Peripartum hysterectomy (life-saving - do not delay)

• TXA 1g IV is now first-line early adjunct - [WOMAN Trial 2017, PMID 28456509]: reduces death from bleeding by 31% if given within 3 hours

2. DIFFICULT FETAL EXTRACTION / IMPACTED HEAD

3. UTERINE INCISION EXTENSION / RUPTURE

• Identify extension early (inspect all edges)
• Repair with delayed absorbable suture (Vicryl/PDS) in 1-2 layers
• For lateral extension into uterine vessels: figure-of-8 sutures, identify and ligate vessels
• Uterine rupture with uncontrolled haemorrhage or extensive damage: Subtotal/total hysterectomy
• Check bladder and ureter integrity after any lateral extension

4. BLADDER INJURY

• Recognised intraoperatively: immediate two-layer repair with 3-0 Vicryl (submucosa + muscularis)
• Foley catheter for 10-14 days postoperatively
• Cystogram before catheter removal to confirm healing
• Ureteric injury: consult urology; ureteric stenting or reimplantation

5. ENDOMYOMETRITIS / SEPSIS

• Most common postoperative complication in obstructed labour
• Treatment: Clindamycin 900mg IV 8-hourly + Gentamicin 1.5mg/kg IV 8-hourly (Creasy & Resnik; French & Smaill systematic review)
• This combination superior to all others (covers penicillin-resistant anaerobes)
• Oral follow-up antibiotics NOT needed once clinical improvement occurs
• If pelvic thrombophlebitis suspected (fever not responding to antibiotics): add IV Heparin - dramatic improvement confirms diagnosis

6. WOUND COMPLICATIONS

7. DVT / PULMONARY EMBOLISM

• DVT: LMWH (Enoxaparin 1mg/kg BD) + compression stockings + anticoagulate 6 weeks
• PE: If haemodynamically stable: heparinisation; if unstable: consider thrombolysis or surgical embolectomy
• RCOG recommends risk stratification and thromboprophylaxis for all CS patients

8. PARALYTIC ILEUS

• NBM, nasogastric aspiration, IV fluids, electrolyte correction
• Neostigmine 2.5mg IV for Ogilvie syndrome (colonic pseudo-obstruction)
• Early mobilisation, chewing gum post-op (reduces ileus duration - meta-analysis evidence)

9. NEONATAL ASPHYXIA

• Senior neonatologist/paediatrician present at delivery
• Neonatal resuscitation: warm, dry, stimulate, suction, bag-mask ventilation, intubation
• APGAR at 1 and 5 minutes; cord blood gases
• Transfer to NICU if needed

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SUMMARY TABLE (Quick Revision)

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KEY REFERENCES

• Williams Obstetrics 26th Ed, Ch. 23 (Abnormal Labour), Ch. 30 (Caesarean Delivery), Ch. 33 (Term Newborn)
• Creasy & Resnik's Maternal-Fetal Medicine, Complications of Cesarean Delivery (p. 960)
• RCOG Green Top Guideline No. 45 (Birth After Previous CS)
• Queensland Clinical Guidelines: Obstructed Labour and Impacted Fetal Head (2025)
• WOMAN Trial (2017) - Tranexamic acid in PPH [PMID: 28456509]
• French & Smaill Cochrane Review - Antibiotic regimens for endometritis post-CS

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OBSTRUCTED LABOUR

DNB Answer - Williams Obstetrics (Ch. 23), Recent Guidelines

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DEFINITION

Williams Obstetrics Ch. 23: "Dystocia literally means difficult labour and is characterised by abnormally slow labour progress."

• Active phase of labour > 12 hours = prolonged labour (which, if unrelieved, becomes obstructed)
• Key distinction: Power alone does NOT cause obstruction - there must be a mechanical block

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INCIDENCE

• Affects 3-6% of all labours globally
• Leading cause of maternal death in developing countries - contributes to >70% of maternal deaths as a contributing factor
• Most common cause of obstetric fistula worldwide

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CAUSES - THE 3 Ps

1. PASSENGER (Fetal Factors)

2. PASSAGE (Maternal Factors)

• Contracted inlet: AP diameter <10 cm, transverse <12 cm
• Contracted midpelvis: interspinous diameter <9 cm (most common site of arrest)
• Outlet contraction: interspinous <8 cm
• Causes: childhood malnutrition, rickets/osteomalacia, trauma (pelvic fracture), kyphoscoliosis

• Uterine fibroids in lower segment
• Ovarian cyst occupying pelvis
• Cervical stenosis (post-conization, carcinoma)
• Vaginal stenosis (FGM, post-repair, congenital)
• Full rectum or bladder (preventable!)
• Pelvic kidney, sacral tumour

3. POWER (Contributory only)

• Uterine hypotonia, incoordinate contractions
• Power alone NEVER causes obstruction but makes it worse

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PATHOPHYSIOLOGY - WHAT HAPPENS IN THE UTERUS

Normal Retraction Ring (Physiological)
    ↓ (if obstruction continues)
Upper segment thickens, contracts harder
Lower segment becomes thin, over-distended
    ↓
BANDL'S PATHOLOGICAL RETRACTION RING forms
(visible/palpable groove at umbilicus level)
    ↓
Lower segment becomes paper-thin
    ↓
UTERINE RUPTURE (catastrophic)

Bandl's Retraction Ring

• Formed at the junction of upper and lower uterine segments
• Normally the physiological ring is at/below umbilicus - when it rises to the umbilicus, it is now PATHOLOGICAL (Bandl's ring)
• Represents impending uterine rupture - treat as emergency
• Queensland Clinical Guidelines (2025): Use bedside ultrasound to identify Bandl's ring in suspected obstructed labour

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CLINICAL FEATURES

MATERNAL FEATURES

• Maternal exhaustion, dehydration, anxiety
• Tachycardia (>100 bpm), pyrexia if infection
• Dehydration: dry tongue, sunken eyes, oliguria

• Uterus continuously tense and tender (tonic contraction)
• Bandl's ring visible as transverse groove at or above umbilicus
• Lower segment is distended, thin, tender to touch
• Round ligaments taut and palpable bilaterally
• Haematuria (bladder compressed between fetal head and pubic symphysis)
• Fetal parts difficult to palpate

• Presenting part: deeply impacted, no descent
• Severe caput succedaneum (+++ to +++)
• Moulding (overlapping of fetal skull bones - grade 2-3)
• Cervix: oedematous, poorly applied, may not dilate further
• Vaginal walls: oedematous
• No progress on repeat examination after 2-4 hours

FETAL FEATURES

• Fetal tachycardia (>160 bpm)
• Meconium-stained liquor
• Late decelerations / variable decelerations on CTG
• Absent fetal movements

ON PARTOGRAPH

• Cervical dilation crosses the Alert Line → assess and plan
• Cervical dilation crosses the Action Line → MANDATORY intervention
• Alert line = expected minimum progress (1 cm/hour in active phase)
• Action line = 4 hours to the right of alert line
• WHO emphasises monitoring caput and moulding as signs of CPD - not just cervical dilation

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DIAGNOSIS

1. No progress in labour for ≥2 hours in active phase despite adequate contractions
2. Signs of obstruction (Bandl's ring, caput, moulding, maternal exhaustion)
3. Partograph: crossing the action line

• CBC (anaemia, leukocytosis)
• Blood group and crossmatch
• Blood glucose, electrolytes, renal function
• Urine: haematuria (bladder compression)
• CTG: fetal distress
• Ultrasound: presentation, estimated fetal weight, amniotic fluid, identify Bandl's ring (Queensland 2025)
• X-ray pelvimetry: rarely done now; CT pelvimetry if genuine CPD suspected

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MANAGEMENT

STEP 1: IMMEDIATE RESUSCITATION (ALWAYS FIRST)

A - Airway + O₂ by face mask 8-10 L/min
B - Breathing assessment
C - Circulation:
    → IV access x2 (large bore 16G)
    → IV fluids: Ringer's Lactate 1L fast (correct dehydration)
    → Blood: CBC, cross-match 2 units, coagulation
    → Urinary catheter (strict I/O; note haematuria)
D - Drugs:
    → Antibiotics: Ampicillin 2g IV + Metronidazole 500mg IV
    → Antacid: Sodium citrate 30 mL orally (aspiration prevention)
    → NPO
E - Evaluate fetus: CTG, fetal heart rate

STEP 2: ASSESS AND DECIDE

1. Is fetus alive or dead?
2. What is the presentation?
3. Is vaginal delivery possible? (Full dilatation + vertex at outlet + no severe CPD)
4. Is uterine rupture present or imminent?

STEP 3: DEFINITIVE MANAGEMENT

A. LIVE FETUS (Most Cases) - Emergency Caesarean Section

• CS is the treatment of choice for most cases of obstructed labour with live fetus
• Indications: CPD, malpresentation, fetal distress, Bandl's ring
• Special considerations in CS for obstructed labour (covered in detail in previous answer)

• Cervix fully dilated (10 cm)
• Head at +2 to +3 station (outlet)
• No significant CPD
• No Bandl's ring or uterine rupture
• Fetus not in severe distress

B. DEAD FETUS (Destructive Operations)

Note: Destructive operations require fully dilated cervix, dead fetus, and MUST be performed by experienced hands under anaesthesia

C. SHOULDER DYSTOCIA (Special Case - Live Fetus)

HELPERR Mnemonic:
H - Call for Help
E - Evaluate for Episiostomy
L - Legs: McRoberts manoeuvre (hyperflexion of thighs)
P - Suprapubic Pressure (NOT fundal)
E - Enter (Rubin II / Woods screw internal rotation)
R - Remove posterior arm
R - Roll to all-fours (Gaskin manoeuvre)

STEP 4: POST-DELIVERY CARE

• Active management of third stage: Oxytocin 10 IU IV immediately at delivery
• Check for and repair all lacerations
• Continue IV antibiotics 5-7 days (high infection risk)
• Bladder catheter for 10-14 days if haematuria present (prevents VVF formation)
• Neonatologist present at delivery; NICU admission if needed
• Monitor for PPH, urine output, wound infection
• DVT prophylaxis: LMWH + compression stockings
• Debrief patient and family

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COMPLICATIONS

MATERNAL COMPLICATIONS

• Uterine rupture (most dangerous - 5-10% mortality)
• Haemorrhage/PPH (uterine atony due to exhausted uterus)
• Shock (hypovolaemic or septic)
• Bladder/bowel injury

• Puerperal sepsis / chorioamnionitis
• Endomyometritis
• Wound infection
• UTI
• DVT / Pulmonary embolism (RCOG: #1 cause of maternal death in UK)
• Anaemia

Williams Obstetrics Ch. 23: "Because of impaired circulation, necrosis may result and become evident several days after delivery as vesicovaginal, vesicocervical, or rectovaginal fistulas."

FETAL/NEONATAL COMPLICATIONS

• Perinatal asphyxia / HIE (hypoxic-ischaemic encephalopathy)
• Stillbirth / perinatal death
• Caput succedaneum (scalp oedema)
• Skull fracture / cephalhaematoma
• Intracranial haemorrhage
• Meconium aspiration syndrome
• Neonatal sepsis (from chorioamnionitis)
• Brachial plexus injury
• Cerebral palsy (long-term)

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PREVENTION

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QUICK REVISION BOX

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KEY REFERENCES

• Williams Obstetrics 26th Ed, Ch. 23 - Abnormal Labour (Cunningham, Leveno et al.)
• Creasy & Resnik's Maternal-Fetal Medicine - Complications of Cesarean Delivery
• Queensland Clinical Guidelines: Prolonged and/or Obstructed Labour (2025)
• WHO IMPAC Guidelines - Managing Complications in Pregnancy and Childbirth
• RCOG Green Top Guideline No. 45 - Birth After Previous Caesarean Birth
• MSF Medical Guidelines - Obstructed Labour Management