The umbilical cord is the sole physical connection between a developing fetus and the placenta. This structure facilitates the transfer of oxygen and nutrients from the maternal circulation to the fetus, while simultaneously removing waste products. Umbilical cord compression occurs when the cord becomes squeezed or flattened, reducing blood flow, oxygen, and nutrient supply to the baby. This condition can happen at any point during pregnancy or childbirth, though it is more common during labor and delivery.
How Umbilical Cord Compression Occurs
Umbilical cord compression can arise from various scenarios and physical mechanisms that impede blood flow. One common cause is the cord wrapping around the baby, known as a nuchal cord. While mild compression is typical in these cases, severe compression is rare. The baby’s movements within the womb, particularly in later stages of pregnancy, can also cause the cord to be squeezed or compressed.
True knots in the umbilical cord can also lead to compression, especially if the cord is unusually long. If these knots tighten, they can significantly restrict the flow of oxygen to the fetus. Another mechanism involves the baby lying on the cord or the cord being pressed between the baby and the mother’s pelvis. Uterine contractions during labor naturally cause some temporary compression of the umbilical cord.
A more serious cause is umbilical cord prolapse, where the cord slips into the birth canal before the baby, typically after the membranes have ruptured. This rare occurrence can lead to the baby’s head compressing the cord as it descends, severely reducing or cutting off oxygen supply. Oligohydramnios, a condition with insufficient amniotic fluid, can also increase the risk of cord compression due to reduced cushioning around the cord.
Identifying Umbilical Cord Compression
Umbilical cord compression is detected through monitoring fetal well-being. A key indicator is changes in the fetal heart rate pattern, specifically variable decelerations, often observed during cardiotocography (CTG). These decelerations represent a sudden decrease in the fetal heart rate below the baseline, followed by a rapid return, indicating a temporary reduction in blood flow.
Diagnostic tools like ultrasound can provide a visual assessment of the cord’s position and evaluate blood flow dynamics. Ultrasound can help identify instances where the cord is wrapped around the baby’s neck or body, or if there are true knots. While mothers do not feel the compression directly, subtle changes in fetal movement, such as a sudden decrease, might prompt medical evaluation.
Regular prenatal tests, including non-stress tests or biophysical profiles, can also reveal abnormal results that suggest cord compression. These tests assess fetal heart rate, movement, breathing, muscle tone, and amniotic fluid volume, providing a comprehensive picture of fetal health.
Addressing Umbilical Cord Compression
Umbilical cord compression can reduce oxygen and nutrient supply to the fetus, potentially leading to fetal distress. Prolonged or severe compression can cause conditions like ischemia (restricted blood supply) and hypoxia (reduced oxygen supply), which may result in fetal heart abnormalities, poor physical development, or, in rare severe cases, brain damage.
Medical interventions to address cord compression vary depending on the severity and persistence of the issue. A common initial strategy involves changing the mother’s position, which can often relieve pressure on the cord. Administering oxygen to the mother may also be employed to increase oxygen availability to the fetus. Intravenous fluids can be given to improve maternal hydration, which might indirectly help improve placental blood flow.
In cases where these conservative measures are insufficient, or if signs of fetal distress persist or worsen, more immediate action becomes necessary. This may include amnioinfusion, a procedure where a sterile fluid is introduced into the uterus to cushion the umbilical cord. For severe or unresolving compression that poses a significant threat to fetal well-being, an emergency delivery, often via Cesarean section, may be required to ensure the baby’s safety.