Umbilical cord prolapse is a rare but extremely serious obstetrical complication that represents a medical emergency during labor or delivery. This event occurs when the umbilical cord descends through the mother’s cervix ahead of the baby’s presenting body part. The primary danger lies in the cord becoming compressed between the fetus and the maternal pelvis, which rapidly compromises the baby’s oxygen supply.
Defining Umbilical Cord Prolapse and Its Classifications
Umbilical cord prolapse is defined by the cord’s anatomical position relative to the baby and the cervix, occurring after the rupture of the amniotic sac membranes. The condition is categorized into two main types. Overt (frank) cord prolapse occurs when the cord descends past the baby’s presenting part and is visible outside the mother’s body or easily felt within the vagina. This situation exposes the cord to potential trauma and compression.
Occult (hidden) cord prolapse is similarly dangerous, but the cord is positioned alongside the baby’s presenting part and has not fully descended past it. The cord is not visible externally and is often only suspected due to changes in the baby’s heart rate pattern. Both types pose a risk because the cord, which carries the baby’s lifeline, can become squeezed between the baby’s body and the wall of the uterus or the pelvis, interrupting blood flow.
Conditions That Increase the Likelihood of Prolapse
Umbilical cord prolapse is often linked to circumstances that prevent the baby’s presenting part from snugly fitting into the lower uterus or pelvis. A common risk factor is fetal malpresentation, such as a breech (bottom-first) or transverse (sideways) position. When the head is not the presenting part, an open space remains through which the cord can easily slip down after the membranes rupture.
An excess amount of amniotic fluid, known as polyhydramnios, also increases the risk. The large volume of fluid can create a forceful rush when the membranes break, washing the cord down. Similarly, having a premature or low birth weight baby increases the likelihood because their smaller size does not fill the maternal pelvis as completely as a full-term baby.
Pregnancies involving multiple babies, such as twins, are associated with a higher incidence of prolapse, especially for the second baby. Medical intervention, specifically the artificial rupture of membranes, also contributes to risk if performed before the baby’s presenting part is well-engaged into the pelvis.
The Immediate Fetal Impact of Cord Compression
Umbilical cord prolapse constitutes an emergency due to the immediate impact compression has on the baby’s oxygen supply. The cord contains two arteries and one vein that transport oxygenated blood and nutrients from the placenta. Compression by the baby’s body or the contracting uterus suddenly and severely restricts this blood flow.
The immediate physiological response to this loss of oxygenated blood flow is a rapid drop in the fetal heart rate, known as bradycardia. This abnormal heart rate pattern is often the first sign detected by medical staff. Reduced blood flow quickly leads to fetal hypoxia, a state of oxygen deprivation to the baby’s tissues and organs.
If compression is not quickly relieved, the lack of oxygen leads to a build-up of acidic waste products, resulting in metabolic acidosis. This cascade of events has a narrow window of time before it causes permanent damage to the baby’s brain and other organs. Exposure of the prolapsed cord to the cooler external environment can also cause vasospasm, restricting blood flow independent of physical compression.
Emergency Medical Intervention and Delivery
Upon confirmation of umbilical cord prolapse, the immediate priority is to relieve pressure on the cord. The first maneuver involves using a gloved hand to manually elevate the baby’s presenting part away from the compressed cord, maintaining continuous upward pressure. Simultaneously, the mother is quickly positioned to use gravity to pull the baby away from the pelvis, such as the Trendelenburg (head-down) or knee-chest position.
Other pressure-relieving techniques include filling the maternal bladder with sterile fluid to lift the baby’s presenting part off the cord. Tocolytics, medications that temporarily slow uterine contractions, may also be administered to minimize the squeezing force. These are temporary measures designed to sustain the baby until definitive treatment can be executed.
The ultimate management is immediate delivery, almost always achieved through an emergency Cesarean section (C-section). This rapid surgical delivery is necessary because the time frame for preventing serious harm from oxygen deprivation is extremely short, measured in minutes. A C-section is only bypassed if the mother is fully dilated and a quick, assisted vaginal delivery is immediately possible.