Obstetrics Simplified - Diaa M. EI-Mowafi

Obstructed Labour

Definition

It is the arrest of vaginal delivery of the foetus due to mechanical obstruction.

Aetiology

Maternal causes

• Bony obstruction: e.g.
  • Contracted pelvis.
  • Tumours of pelvic bones.
• Soft tissue obstruction:
  • Uterus: impacted subserous pedunculated fibroid, constriction ring opposite the neck of the foetus.
  • Cervix: cervical dystocia.
  • Vagina: septa, stenosis, tumours.
  • Ovaries: Impacted ovarian tumours.

Foetal causes

• Malpresentations and malpositions: e.g.
  • Persistent occipito-posterior and deep transverse arrest,
  • Persistent mento-posterior and transverse arrest of the face presentation.
  • Brow,
  • Shoulder,
  • Impacted frank breech.
• Large sized foetus (macrosomia).
• Congenital anomalies: e.g.
  • Hydrocephalus.
  • Foetal ascitis.     
  • Foetal tumours.
• Locked and conjoined twins.

Diagnosis

It is the clinical picture of obstructed labour with impending rupture uterus (excessive uterine contraction and retraction).

History

• prolonged labour,
• frequent and strong uterine contractions,
• rupture membranes.

General examination

It shows signs of maternal distress as:

• exhaustion,
• high temperature (³ 38oC),   
• rapid pulse,
• signs of dehydration: dry tongue and cracked lips.

Abdominal examination

• The uterus:
  • is hard and tender,
  • frequent strong uterine contractions with no relaxation in between (tetanic contractions).
  • rising retraction ring is seen and felt as an oblique groove across the abdomen.
• The foetus:
  • foetal parts cannot be felt easily.
  • FHS are absent or show foetal distress due to interference with the utero-placental blood flow.

Vaginal examination

• Vulva: is oedematous.            
• Vagina: is dry and hot.
• Cervix: is fully or partially dilated, oedematous and hanging.
• The membranes: are ruptured.
• The presenting part: is high and not engaged or impacted in the pelvis. If it is the head it shows excessive moulding and large caput.
• The cause of obstruction can be detected.

Differential diagnosis

• Constriction ring.  
• Full bladder.
• Fundal myoma.

Complications

• Maternal:
  • Maternal distress and ketoacidosis.
  • Rupture uterus.
  • Necrotic vesico-vaginal fistula.
  • Infections as chorioamnionitis and puerperal sepsis.
  • Postpartum haemorrhage due to injuries or uterine atony.
• Foetal:
  • Asphyxia.       
  • Intracranial haemorrhage from excessive moulding.
  • Birth injuries.
  • Infections.

Management

• Preventive measures:
  • Careful observation, proper assessment, early detection and management of the causes of obstruction.
• Curative measures:
  • Caesarean section is the safest method even if the baby is dead as labour must be immediately terminated and any manipulations may lead to rupture uterus.

Links

• Dystocia : Guidelines, reviews

• Labor, delivery : Guidelines, reviews

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Edited by Aldo Campana,