Cord Prolapse After Amniotomy

Cord prolapse after amniotomy is descent of the umbilical cord alongside or in front of the presenting part immediately after artificial rupture of membranes. It is far more likely when the head is not engaged or the lie is abnormal. It matters because it is an iatrogenic obstetric emergency, in which the cord is compressed within minutes and the fetus becomes hypoxic.

• Risk factors: unengaged or high head, malpresentation (breech, transverse lie), polyhydramnios, prematurity, twin pregnancy, long cord, uncontrolled gush of liquor.
• Amniotomy is done only when the head is engaged, with a hand in place to control the drainage of liquor.
• The cord is checked at once and after the next contractions.

After rupture, a loop of cord is felt in the vagina or seen at the vulva, with or without pulsation, and the fetal heart rate falls or shows variable or prolonged decelerations. Women may report a sensation of something passing.

• Pulsating cord below or beside the presenting part.
• Sudden bradycardia after the membranes are ruptured.
• Differential diagnosis: cord presentation, vasa previa, placental abruption, uterine hyperstimulation, fetal distress from other cause.
• Complications: fetal hypoxia and acidosis, hypoxic ischaemic encephalopathy, cerebral palsy, stillbirth, neonatal death, emergency caesarean section, maternal distress.

The diagnosis is immediate and clinical, by examination after amniotomy.

• Vaginal examination at the time of rupture and again after the next contraction: cord felt below or beside the presenting part; pulsation shows life.
• Cardiotocography or auscultation of the fetal heart for 1 minute after rupture and after each of the next 3 contractions.
• Liquor colour and volume; position and station of the head.
• Do not delay delivery for investigation.

The principle is to relieve cord compression at once and deliver by the fastest safe route, with a decision to delivery time as short as possible.

• Supportive: call for senior obstetric, anaesthetic and neonatal teams; push the presenting part up manually with two fingers and keep them there until delivery; knee chest or exaggerated left lateral head down position; do not handle a cord outside the vulva more than needed, and keep it warm in a saline soaked swab; fill the bladder with sodium chloride 0.9 percent 500 to 750 mL through a catheter and clamp it; oxygen 10 L/minute; two cannulae.
• Pharmacological: terbutaline 0.25 mg subcutaneous once to reduce contractions while preparing for delivery; Ringer's lactate 500 to 1000 mL IV over 15 minutes; cefazolin 2 g IV before caesarean section; oxytocin 10 IU IM after birth; newborn resuscitation with 5 inflation breaths then 30 to 60 breaths per minute by bag and mask, with chest compressions in a ratio of 3 to 1 if the heart rate stays below 60 per minute after 30 seconds of effective ventilation, and adrenaline 0.01 to 0.03 mg/kg IV (0.1 to 0.3 mL/kg of 1 in 10,000) if the heart rate stays low.
• Procedures: category 1 caesarean section aiming for delivery within 30 minutes of diagnosis (as fast as possible for bradycardia), under general anaesthesia unless a working epidural can be topped up at once; assisted vaginal delivery by vacuum or forceps if fully dilated and the head is low; manual replacement of the cord is not done.
• Special groups: the presenting part must not be allowed to descend onto the cord when the woman is moved or in theatre; women outside theatre capable facilities are transferred in the knee chest position with the presenting part held up and the bladder filled.
• Red flags: bradycardia below 100 beats per minute, absent cord pulsation, thick meconium, delay in decision to delivery beyond 30 minutes.
• Follow-up: umbilical cord blood gas; newborn Apgar score and neurological examination; observation for encephalopathy over 72 hours if depressed; maternal debrief and review at 6 weeks.