Which condition significantly increases the risk of umbilical cord prolapse during labor?

Polyhydramnios, or an excess of amniotic fluid, significantly increases the risk of umbilical cord prolapse during labor. The abundance of fluid allows for greater fetal movement, which can lead to a situation where the umbilical cord slips ahead of the presenting part of the fetus. This is particularly critical during labor as the head descends into the birth canal. If the presenting part does not adequately engage, the cord can become trapped between the fetus and the cervix, compromising fetal blood flow and oxygenation.

In the case of dilation being at a low level, such as 3 cm, there is typically still a considerable amount of time before delivery, and the fetus is not yet engaged in the birth canal. This reduces the likelihood of cord prolapse at that stage. In situations of single gestation and vertex presentation, the positional stability of the fetus further mitigates the risks associated with umbilical cord prolapse, as these scenarios generally involve a well-engaged fetal head that acts as a barrier to the cord, preventing it from slipping past. Polyhydramnios creates a different dynamic altogether that can lead to an increased risk for this complication.