Complications of the third stage of labour

1. Postpartum haemorrhage (the commonest and most dangerous)

• Tone: uterine atony is the commonest cause.
• Trauma: cervical, vaginal or uterine lacerations, episiotomy bleeding, and uterine rupture.
• Tissue: retained placenta or membranes, and placenta accreta.
• Thrombin: coagulopathy, either spontaneous or iatrogenic.

• Monitor vital signs frequently, set up large-bore IV access, give crystalloid and prepare for transfusion.
• Look for the source: atony, lacerations, coagulopathy, accreta and inversion. Ultrasound helps to find retained tissue or clots.
• Give oxytocin infusion, 20-30 units in 1000 mL at no more than 100 mU/min. Avoid bolus doses because they cause hypotension.
• Give methylergometrine 0.2 mg IM. Never give it IV, because of the risk of hypertension and vasospasm.
• Give carboprost (15-methyl PGF2α) 250 μg IM, repeated if needed. Use it with great caution in asthma or cardiovascular disease.
• Misoprostol is an option, especially where oxytocin is unavailable.
• If bleeding persists, use a Foley or Bakri balloon tamponade, uterine packing, or selective pelvic artery embolisation.
• The last resort is laparotomy with arterial ligation (including B-Lynch compression suture) and then hysterectomy.

2. Retained placenta

• If the placenta has not been delivered after 30 minutes of gentle cord traction and uterine massage, remove it manually. Use general anaesthesia, or IV tocolysis with adequate analgesia.
• Nitroglycerin is a useful tocolytic here: 400 μg sublingual spray (1-2 sprays, repeated every 3-5 minutes up to 3 doses) or 50-150 μg IV.
• Risk factors include maternal age over 30, extreme preterm delivery, and stillbirth.
• Placenta accreta is the rare cause. Chorionic villi attach directly to the myometrium because the decidua basalis is defective. It is associated with placenta praevia and prior caesarean. If manual removal fails, hysterectomy is usually needed to avoid catastrophic haemorrhage. Conservative management is possible in focal cases if fertility preservation is paramount.
• Retained fragments can also cause delayed PPH and infection.

3. Uterine inversion

• Mechanism: it is linked to fundal placental implantation, which thins the myometrium. Excessive cord traction or fundal pressure can then turn the uterus inside out. Connective tissue disorders and uterine anomalies also predispose.
• Complete inversion: the fundus protrudes past the cervix as a beefy-red mass at the introitus.
• Incomplete inversion: the fundus does not pass the external os. Suspect it when there is PPH and the fundus cannot be felt abdominally. Ultrasound helps with diagnosis.
• Presentation: pain, haemorrhage and neurogenic shock that is out of proportion to the blood loss.
• Management:
  • Resuscitate and call the anaesthetist early.
  • Reinvert immediately with firm, steady pressure on the fundus (Johnson manoeuvre). Tocolytics (magnesium sulfate, β-mimetics or nitroglycerin) or general anaesthesia may be needed.
  • Reinversion is easier if the placenta is left in place until afterwards. Opinions differ on this.
  • If this fails, go to laparotomy with the Huntington procedure (traction on the round ligaments), or the Haultain procedure (posterior incision of the fundus).
  • Give uterotonics once the uterus is replaced.
• Delay allows cervical constriction and oedema, with a risk of necrosis and bladder or urethral injury.

4. Other complications

• Genital tract trauma: cervical, vaginal and perineal tears. Inspect and repair promptly after delivery.
• Uterine rupture: this is rare. Previous caesarean is the main risk factor. It presents with pain, bleeding and a palpable defect.
• Hypovolaemic shock and its sequelae: DIC, acute tubular necrosis, ARDS and Sheehan syndrome (pituitary necrosis). These are avoidable with careful observation and aggressive treatment of haemorrhage.
• Amniotic fluid embolism: this can present around delivery with collapse and DIC. It is not in the textbook passages I read, so this comes from my own knowledge.
• Prolonged third stage: this is itself a risk factor for PPH. A 2025 systematic review and meta-analysis (PMID 39032724) examined the length of the third stage and adverse maternal outcomes after vaginal birth. Its title questions whether "prolonged third stage" should be redefined. I did not read the full paper, so check it if you need the current thresholds.
• Complications of the interventions themselves:
  • Oxytocin: water intoxication and hypotension.
  • Ergometrine: hypertension and vasospasm.
  • Carboprost: bronchospasm.
  • Manual removal: pain and infection.

Quick summary