Umbilical Cord Prolapse

What is a prolapsed umbilical cord?

The umbilical cord is the tube-like structure extending through the placenta to the baby within the uterus, acting as his lifeline, carrying oxygen and all the necessary nutrients from the mother’s bloodstream ^[1]. A prolapse may occur before or during delivery when the cord comes out the cervix to the vagina before the baby can come out. It may then make it difficult for the baby to pass through the cervix, or even get entangled with his body, leading to further complications ^[2].

Types of umbilical cord prolapse

Overt cord prolapse: Sometimes, a prolapse occurs if there is a gap between the fetal presenting part and the pelvic opening, after the rupture of membranes. In this type of UCP, the cord can be seen coming ahead of the fetus during delivery ^[3].

Occult cord prolapse: Here the cord drops alongside the fetal presenting part instead leading the way ^[4]. It can occur with or without the waters breaking.

What causes a prolapse of the umbilical cord?

It is not always possible to foresee the chances of having the complication or to determine the exact causes responsible for it.

Certain risk factors have been identified, including:

Premature rupture of membranes, one of the most common risk factors, may allow enough space for the umbilical cord to slip out first if the baby is too high in the uterus at the time of the rupture ^{[5, 6]}
Having twins or more as the first baby may bring the cord ahead of the second baby ^[7]
Premature labor and delivery ^[2]
The umbilical cord being longer than usual ^[4]
Polyhydramnios or the amniotic fluid levels being too high ^[8]
Abnormal presentation of the baby, such as a transverse or breech presentation, where the baby is in a sideways lie or a feet-down position, often leaving space for the umbilical cord to drop ^[9]
A low lying placenta ^[10]
Planned home birth or delay in reaching the hospital after the waters break ^[4]

Some studies suggest an association between male fetuses and an increased risk of a cord prolapse ^[11].

Cord presentation

Also known as the funic presentation, it refers to a certain fetal presentation where the cord is situated below the fetal presenting part, pointing toward the lower uterine segment. It is considered normal up to week 32 as the cord often moves out of the way before labor starts. However, if it continues in the same position even in the following weeks, there is a significant risk of a UCP ^[12].

Is it possible to prevent a UCP?

It is usually not possible to predict or prevent a cord prolapse as the common risk factors cannot be prevented.

Risks of a prolapsed cord: How does it affect the baby?

As the cord prolapses, it has a great risk of being squashed by the baby, reducing or cutting off the blood flow as well as oxygen supply to him ^[13]. So, an immediate delivery becomes unavoidable, as extremely low levels of oxygen may lead to fetal hypoxia, long-term birth defects like brain damage or even death of the baby ^[14]. Moreover, being exposed to air can irritate and cool the umbilical cord, causing constriction of the blood vessels in it (vasospasm) ^[4]. The resulting lack of blood supply may then lead to birth asphyxia (unconsciousness due to lack of oxygen), cerebral palsy and hypoxic–ischemic encephalopathy ^[11].

Studies show the death rates associated with it to have dropped significantly due to the rapid advancement of modern medical procedures with the current rates of mortality ranging between 30 and 165 in every 1000 live births ^{[10, 24]}.

Prolapsed cord signs: How is it diagnosed?

Feeling the cord dropping into the vagina or your midwife seeing the cord come out before the presenting part of the baby are the most obvious ways to confirm a UCP ^[15]. A pelvic exam may also help with the diagnosis.

The doctor checks the baby’s heart rate on a fetal Doppler following the waters breaking. A prolapse is suspected in case it suddenly drops below 120 beats a minute ^{[2, 16]}, as it might indicate a lack of oxygen supply through the cord ^[14]. An ultrasound scan performed before delivery to check the cord compression may also detect the problem; however, further tests are often necessary to confirm it ^[17].

Treatment and management of umbilical cord prolapse

Prolapsed cord is a medical emergency to be dealt with by your doctor as soon as possible ^[18], as the risks of harm to the baby increases greatly with any delay ^[2]. It does not have any long-term effects on the baby when managed promptly and properly ^[14].

In case of an occult prolapse, the mother getting into a position that would relieve some of the pressure from the cord may help to keep the blood flow normal, preventing the oxygen loss ^[15]. The fetal heart rate should gradually become normal in such a case. However, if the monitor continues to show abnormal heart rate patterns, an immediate c-section may be necessary ^[19].

An overt prolapse usually requires an immediate delivery, with the doctor holding the baby off the cord until he is delivered safely ^[15]. A quick vaginal delivery using a vacuum extractor or forceps may be possible in full term or near-full term pregnancies if the baby’s head is already engaged or if he is lying quite low in the birth canal. However in most cases, a cesarean section is performed. ^[20].

How common is the umbilical cord prolapse?

It is relatively rare in normal pregnancies, with the incidence rate ranging between 0.1% and 0.6% for babies in a cephalic presentation later in the third trimester ^[21]. UCP occurs in around 1% of women having a breech baby.