An umbilical cord prolapse is a rare but serious obstetrical emergency that occurs when the cord descends through the cervix into the vagina before the baby. It affects approximately 0.1% to 0.6% of all births. The condition is considered an immediate life threat to the baby because it can quickly restrict the flow of oxygenated blood. Rapid recognition and intervention are necessary to prevent severe complications.
The Mechanism of Umbilical Cord Prolapse
The umbilical cord connects the baby to the placenta, carrying oxygen and nutrients through three blood vessels. A prolapse happens when the cord slips past the fetal presenting part, which is usually the head or buttocks, and comes to rest either alongside or below it. This descent typically occurs after the amniotic sac, or “water,” has ruptured.
The primary danger is mechanical compression of the cord between the baby’s body and the mother’s pelvis or cervix. This squeezing action cuts off the blood supply, leading to a sudden and severe reduction in the oxygen the baby receives. Cord prolapse is categorized into two main types based on the cord’s position relative to the baby.
An overt prolapse is when the cord descends past the presenting part and is visible in the vagina or outside the mother’s body. An occult or incomplete prolapse is when the cord lies alongside the presenting part but is not visible externally. In both cases, the cord is vulnerable to compression, potentially causing fetal hypoxia.
Factors That Increase the Risk
A common risk factor is fetal malpresentation, where the baby is positioned abnormally, such as in a breech presentation or a transverse lie. These circumstances prevent the baby’s presenting part from fitting snugly against the cervix, leaving an open space through which the cord can drop when the membranes rupture.
Prematurity and low birth weight also increase the risk because a smaller baby is less likely to fill the pelvic inlet completely. Polyhydramnios, which is an excessive amount of amniotic fluid, can contribute to the condition because the sudden rush of fluid upon membrane rupture can sweep the cord down with it. Additionally, a procedure known as artificial rupture of membranes, or amniotomy, carries a risk if the baby’s head is not properly engaged in the pelvis at the time.
Other conditions like a multiple gestation pregnancy and fetal abnormalities can also predispose a pregnancy to prolapse. These factors create a situation of unsealed space between the baby and the lower uterus. This allows the cord to move into a position where it can be compressed by the descending baby.
Recognizing the Emergency and Immediate Action
The most obvious sign for a person outside of a clinical setting is feeling the umbilical cord in the vagina after the water has broken. If the cord is felt, it may be pulsating, which indicates the baby is still receiving blood flow.
If this occurs, the single most important step is to call for emergency medical services without delay. Crucially, the cord should not be handled or pushed back inside the vagina. This manipulation can cause the blood vessels to spasm and worsen the oxygen deprivation.
While awaiting the arrival of medical personnel, the mother must assume a position that uses gravity to relieve pressure on the cord. The knee-chest position, where the mother is on her hands and knees with her chest on the floor and hips elevated, is often recommended. Alternatively, the Trendelenburg position, where the mother lies on her back with her feet elevated higher than her head, can also help.
Definitive Medical Treatment
Once the patient arrives at the hospital, the definitive medical intervention is immediate delivery to resolve the compression and restore full oxygen supply. This management is a rapid sequence of actions focused on minimizing the time the cord is under pressure.
Until immediate delivery can be achieved, a healthcare provider will insert a hand into the vagina to manually elevate the baby’s presenting part off the cord. This manual elevation is maintained continuously, even while rushing to the operating room, to physically protect the cord from being crushed. In some cases, the maternal bladder may be rapidly filled with sterile saline through a catheter, a technique that raises the uterus and can temporarily float the baby up, further relieving cord compression.
The fastest and safest route for delivery is almost always an emergency Cesarean section. Only in rare circumstances, such as when the cervix is fully dilated and a vaginal delivery is deemed imminent and faster, would a non-surgical delivery be considered.