Pathophysiology
Clinical meaning
Umbilical cord prolapse occurs when the cord descends through the cervix ahead of or alongside the fetal presenting part after membrane rupture, resulting in cord compression between the fetus and maternal pelvis. This compression occludes umbilical blood flow, causing acute fetal hypoxia and bradycardia. Overt prolapse (cord visible at introitus or palpable in vagina) is an obstetric emergency requiring delivery within minutes. Occult prolapse (cord compressed alongside the presenting part but not palpable) presents as variable or prolonged decelerations on fetal monitoring. Without rapid intervention, sustained cord compression leads to fetal acidosis, hypoxic-ischemic encephalopathy, and death.