8.2 Umbilical Cord Prolapse & Feto-Vascular Emergencies

Classification, Mechanics & Pathophysiology

Umbilical cord prolapse is an acute catastrophic obstetric emergency in which the umbilical cord slips ahead of or alongside the fetal presenting part, leading to severe mechanical compression and acute vasospasm of the umbilical vessels. The umbilical cord contains two umbilical arteries carrying deoxygenated fetal blood to the placenta and one large umbilical vein transporting oxygenated, nutrient-rich blood from the placenta to the fetus, all encased within the protective, gelatinous extracellular matrix of Wharton's jelly.

When the amniotic membranes rupture in the presence of an unengaged or poorly applied presenting part, the sudden rush of amniotic fluid sweeps the buoyant umbilical cord downward past the fetal head or breech into the lower uterine segment, cervical canal, vagina, or outside the introitus. The presenting part then descends firmly against the maternal bony pelvic inlet, clamping the umbilical vessels against the rigid pelvic bones.

+---------------------------------------------------------------------------------------------------+
|                             CLASSIFICATION OF CORD PROLAPSE VARIATIONS                            |
+---------------------------------------------------------------------------------------------------+

    [ 1. OVERT CORD PROLAPSE ]
    • Membranes are RUPTURED.
    • Cord descends ahead of the presenting part through the dilated cervix.
    • Loops of cord are directly visible protruding from the introitus or palpable
      as a pulsating, soft, cord-like mass on digital vaginal examination.
    • Highest immediate risk of complete circulatory occlusion and hypothermia-induced vasospasm.
                                                  │
    [ 2. OCCULT CORD PROLAPSE ]                   │
    • Membranes may be INTACT or RUPTURED.        │
    • Cord lies alongside (lateral to) the        │   [ 3. FUNIC / CORD PRESENTATION ]
      fetal presenting part.                      │   • Membranes are INTACT.
    • Neither visible nor easily palpable on      │   • Cord lies between the presenting part
      routine digital examination.                │     and the intact amniotic membranes at
    • Suspected when repetitive, severe variable  │     the internal cervical os.
      decelerations occur during contractions.    │   • Visible on transvaginal Doppler ultrasound.
                                                  │   • High risk of overt prolapse upon ROM.

Dual Pathophysiology: Mechanical Occlusion & Cold-Induced Vasospasm

Fetal compromise in cord prolapse results from two distinct mechanisms:

1. Direct Mechanical Occlusion: Compression forces exceeding umbilical vein pressure (15–20 mmHg) collapse the thin-walled umbilical vein, immediately halting oxygenated venous return to the fetal right atrium. Subsequent compression exceeding umbilical arterial pressure (50–60 mmHg) obstructs fetal cardiac afterload, triggering a profound, sustained vagal-mediated bradycardia, acute myocardial ischemia, and rapid metabolic acidosis.
2. Hypothermia-Induced Vasospasm: When overt loops of cord protrude through the vaginal introitus into the ambient room air, cooling of the cord and direct tactile irritation trigger intense smooth muscle contraction in the muscular walls of the umbilical arteries and vein (vasospasm). This vasospasm persists even if mechanical compression is temporarily relieved. Clinical rule: Never handle the cord excessively, and NEVER attempt to push protruding cord loops back up into the uterine cavity. Exposed cord must be gently covered with warm, sterile, normal saline-soaked gauze to preserve vessel patency and prevent desiccating vasospasm.

Risk Factors & Predisposing Clinical Scenarios

Umbilical cord prolapse complicates approximately 0.1% to 0.6% of all deliveries, but reaches over 10% to 15% in high-risk obstetric presentations. Any factor that prevents the fetal presenting part from tightly fitting into the maternal lower uterine segment and pelvic inlet creates a pathway for the cord to prolapse upon rupture of membranes.

Diagnostic Recognition & EFM Tracing Patterns

The onset of umbilical cord prolapse is almost invariably marked by an immediate, dramatic change on the electronic fetal monitoring (EFM) tracing:

• Sudden Severe Prolonged Deceleration / Bradycardia: The fetal heart rate abruptly drops from baseline to <90 bpm (often 60–80 bpm) that persists without recovery.
• Repetitive Severe Variable Decelerations: Deep, abrupt 'V' or 'U'-shaped drops in FHR with loss of variability occurring with or between contractions.

Core Inpatient Nursing Standard: Digital vaginal examination must be performed IMMEDIATELY following any spontaneous rupture of membranes (SROM), artificial rupture of membranes (AROM), or sudden unexplained fetal bradycardia to rule out umbilical cord prolapse.

Upon digital examination, the nurse may palpate a smooth, soft, pulsatile, tortuous cord loop within the cervical canal or vaginal vault. If pulsation has ceased, the fetus may still be viable; pulselessness reflects severe external compression or hypothermic vasospasm, not necessarily fetal death. Emergency resuscitation must proceed with maximal urgency.

Step-by-Step Emergency Nursing Management Protocol

+---------------------------------------------------------------------------------------------------+
|                         EMERGENCY PROTOCOL FOR OVERT CORD PROLAPSE                                |
+---------------------------------------------------------------------------------------------------+

    [ STEP 1 ] - CALL FOR IMMEDIATE HELP & STAT EMERGENCY CESAREAN
                 • Shout for help; activate Code OB / Obstetric Emergency Alarm.
                 • Direct team to notify: Attending Obstetrician, Anesthesia, Neonatal Resuscitation Team.
                 • Call OR stat for Crash Cesarean Section; announce time of event.
                                                  │
                                                  ▼
    [ STEP 2 ] - IMMEDIATE CONTINUOUS MANUAL ELEVATION OF PRESENTING PART
                 • Insert sterile gloved hand (or double-gloved hand) into the vagina.
                 • Place fingers/palm against the hard fetal presenting part (vertex or breech).
                 • Push the presenting part UPWARD and OFF the umbilical cord into the abdominal cavity.
                 • MAINTAIN THIS POSITION CONTINUOUSLY! Do not remove hand until surgeon delivers
                   the fetal head at cesarean delivery.
                                                  │
                                                  ▼
    [ STEP 3 ] - REPOSITION THE PATIENT TO UNLOAD PELVIC GRAVITY
                 • Place patient immediately into one of three positions:
                   a) KNEE-CHEST POSITION (Patient on knees, chest flat on bed, buttocks in air)
                   b) STEEP TRENDELENBURG POSITION (Bed tilted with head down 30-45 degrees)
                   c) EXAGGERATED SIMS POSITION (Left lateral with hips elevated on two firm pillows)
                                                  │
                                                  ▼
    [ STEP 4 ] - PROTECT EXPOSED UMBILICAL CORD
                 • If cord protrudes outside vagina: Wrap gently with warm, sterile saline-soaked gauze.
                 • DO NOT attempt to push the cord back inside the vagina or uterus!
                 • DO NOT manipulate or palpate the cord excessively (prevents vasospasm).
                                                  │
                                                  ▼
    [ STEP 5 ] - ADJUNCTIVE INTRAUTERINE RESUSCITATION MEASURES
                 • Discontinue Oxytocin / Pitocin infusion immediately.
                 • Administer 100% Oxygen via non-rebreather mask at 10 L/min to mother.
                 • Rapidly infuse IV crystalloid fluid bolus (500-1,000 mL Lactated Ringer's).
                 • Administer Tocolytic: TERBUTALINE 0.25 mg subcutaneously to abolish contractions
                   and relieve contraction-induced cord compression.
                 • Bladder Filling Technique (if OR transfer is delayed >15-20 min):
                   Insert Foley catheter; instill 500-750 mL sterile normal saline into bladder;
                   clamp catheter to elevate lower uterine segment and fetal head; drain in OR.
                                                  │
                                                  ▼
    [ STEP 6 ] - RAPID OPERATIVE DELIVERY
                 • Transport immediately to OR while maintaining manual elevation and maternal position.
                 • Nurse remains scrubbed under sterile drapes beneath the table holding up the head.
                 • Execute emergency cesarean delivery under general or rapid spinal anesthesia.
                 • (Vaginal delivery is ONLY attempted if cervix is 10 cm fully dilated, station is +3/+4,
                   and experienced provider can perform immediate, effortless vacuum/forceps or breech delivery).

Critical Clinical Details on Emergency Adjuncts

1. The Bladder-Filling Technique (Vago's Method): In cases where the operating room is occupied or transport to a surgical suite will take longer than 15 to 20 minutes, instilling 500 to 750 mL of warm sterile normal saline through an indwelling Foley catheter into the urinary bladder distends the anterior bladder wall. The distended bladder acts as a physical hydraulic wedge, pushing the lower uterine segment and fetal presenting part cephalad and relieving pressure on the prolapsed cord. The catheter is clamped. Once in the surgical suite immediately prior to skin incision, the clamp is released to empty the bladder and prevent surgical bladder laceration.
2. Tocolysis for Cord Decompression: Administering Terbutaline 0.25 mg subcutaneously is a highly effective pharmacological adjunct. Tocolysis temporarily halts myometrial contractions, eliminating the recurring, powerful spikes in intrauterine pressure that compress the cord against the presenting part.
3. Preserving Maternal Communication: Rapid, structured closed-loop communication among the team and clear, calm explanations to the laboring patient and partner prevent panic and ensure physical cooperation during rapid maternal repositioning and transport.