Impending Uterine Rupture

Impending uterine rupture is the stage before the uterine wall tears, when the lower segment is overstretched and thin, the contraction ring is raised, and the fetus is at risk. It occurs in obstructed labour, in labour after a uterine scar and with excessive oxytocin or misoprostol. It matters because immediate caesarean section prevents rupture and its haemorrhage, fetal death and loss of the uterus.

• Risk factors: obstructed labour, previous caesarean or uterine surgery, grand multiparity, oxytocin or misoprostol use, macrosomia, malpresentation.
• A bandl ring is a groove between the upper and lower segments that rises toward the umbilicus.
• Signs may be subtle in a woman with an epidural.

Women have severe, constant pain between contractions, restlessness and distress, with tenderness over the lower segment or the scar. The uterus may be tense and hard, and a ridge (bandl ring) appears across the lower abdomen.

• Frequent strong contractions with a tender stretched lower segment.
• Round ligaments tense like cords, haematuria.
• Differential diagnosis: obstructed labour, uterine hyperstimulation, placental abruption, scar dehiscence, chorioamnionitis, urinary retention, strong normal contractions.
• Complications: uterine rupture, haemorrhage, fetal hypoxia and death, hysterectomy, bladder injury, sepsis, maternal death.

The diagnosis is clinical, with urgent confirmation of the cause.

• Abdominal examination: bandl ring, tender lower segment, tense round ligaments, fetal lie and fifths of head palpable.
• Vaginal examination: oedematous cervix, caput and moulding of 3 plus, hot dry vagina, blood-stained urine on catheterisation.
• Cardiotocography showing late decelerations, bradycardia or tachysystole; maternal pulse above 100 per minute.
• Haemoglobin and group and cross-match 2 to 4 units; do not delay surgery.

The principle is to stop uterotonic drugs, resuscitate, relax the uterus and deliver by emergency caesarean section.

• Supportive: stop oxytocin and remove misoprostol or dinoprostone; left lateral position; two large-bore cannulae; Ringer's lactate 1 litre IV over 30 minutes; oxygen 10 L/minute; urinary catheter; group and cross-match; senior obstetric and anaesthetic team; consent for hysterectomy.
• Pharmacological: terbutaline 0.25 mg subcutaneous once while preparing for theatre; morphine 2.5 to 5 mg IV titrated for pain; cefazolin 2 g IV plus metronidazole 500 mg IV before incision; ampicillin 2 g IV 6-hourly plus gentamicin 5 mg/kg IV once daily plus metronidazole 500 mg IV 8-hourly for obstructed labour or fever; oxytocin 10 IU IM after birth, then 20 IU in 1 litre Ringer's lactate at 125 mL per hour for 4 hours; tranexamic acid 1 g IV over 10 minutes if bleeding exceeds 500 mL; newborn resuscitation with bag and mask.
• Procedures: emergency category 1 caesarean section, with inspection of the lower segment, bladder and broad ligaments, and repair or hysterectomy if rupture has occurred; a dead fetus with obstruction allows destructive delivery by an experienced operator if the uterus is intact; bladder catheter for 7 to 14 days after obstructed labour.
• Special groups: a woman with a previous scar and any of these signs has caesarean section at once without waiting for full confirmation; fetal death with obstructed labour has prolonged antibiotics and close monitoring for sepsis.
• Red flags: bandl ring, constant severe pain, sudden relief of pain, bleeding, shock, fetal bradycardia, haematuria.
• Follow-up: haemoglobin at 24 hours; review for wound infection and fistula; counselling that later births are by planned caesarean section at 36 to 37 weeks; review at 6 weeks.