Picture a happy couple getting ready to drive to the hospital for the birth of their baby. Her water has broken, contractions are 7 or 8 minutes apart, and things seem to be going well. Then the pregnant woman goes to the toilet and feels the baby's umbilical cord protruding from her vagina.
An uneventful pregnancy has taken an emergency turn.
How Does It Happen?
A cord prolapse occurs when the umbilical cord gets between the fetus and its exit--the birth canal. This can happen even before the sac of amniotic fluid has broken, but more commonly occurs when the water breaks and the fetal head is not yet fully engaged in the pelvis and thus blocking the cervix.
A rush of fluid, especially if there is excessive fluid (polyhydramnios), can carry the cord into the birth canal. When the baby is not in quite the right position for delivery, for example, when the fetus is in a breech or transverse position, or the presenting part is an arm or shoulder, then the cord may pass through the cervix before the rest of the baby has gone through.
The fetus is now endangered because any pressure on the cord will reduce the flow of blood and oxygen to the baby. If there is only a small amount of pressure on the cord, then fetal hypoxia may set in gradually, but if the cord is completely pinched off, then the fetus can asphyxiate in minutes. This is why prompt action is needed to save the baby.
The risk of cord prolapse is higher for the second baby in the delivery of twins, for mothers with polyhydramnios, or fetuses in a transverse or breech position. Occasionally, a fetus may turn from a 'right' to a 'wrong' position during labor, so a cord prolapse is not predictable. According to an article on cord prolapse from November 2005, in the Online Medical Library titled The Merck Manuals, breech babies are found at the end of only 2-3% of full-term pregnancies. In mid-pregnancy, a baby in the breech or transverse position is usually not at risk. A prolapsed cord occurs in only about 1 in 1000 deliveries, but is something to be aware of because it is life-threatening to the fetus.
Medical Consequences
Treatment should begin as soon as the prolapse is discovered. If cord prolapse is suspected because of an abnormal fetal heart rate pattern, then monitoring should continue during treatment. Treatment will vary depending on the baby's position, condition, and the stage of labor. In some cases, changing the mother's position to chest-to-knees or elevating her hips may relieve pressure on the cord, allowing the baby's heart rate to return to normal. The doctor may try lifting the fetal presenting part in order to take pressure off the cord. The mother may be given drugs to reduce her contractions, if birth is not imminent.
If the mother's cervix is fully dilated, and the fetus is head down and low in the birth canal, it may still be possible for the doctor to get the baby out safely using a vacuum extractor or forceps. Sometimes a breech baby can still be delivered quickly through the vagina.
In many cases, an emergency c-section (cesarean) is the safest option for the baby. Sometimes the baby will have to be resuscitated, or suffers organ damage as a result of hypoxia.
In the case mentioned above, an ambulance was called and a paramedic relieved pressure on the still-pulsing cord until arrival at a hospital. An emergency c-section was performed and the infant suffered no ill consequences.
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