The prolapsed umbilical cord may be
Both are uncommon.
In occult prolapse, the cord is often compressed by a shoulder or the head. The only clue may be a fetal heart rate pattern (detected by fetal monitoring) that suggests cord compression and progression to hypoxemia (eg, severe bradycardia, severe variable decelerations).
Changing the woman’s position may relieve pressure on the cord; however, if the abnormal fetal heart rate pattern persists, immediate cesarean delivery is necessary.
Overt prolapse occurs with ruptured membranes and is more common with breech presentation or a transverse lie. Overt prolapse can also occur with vertex presentation, particularly if membranes rupture (spontaneously or iatrogenically) before the head is engaged.
Treatment of overt prolapse begins with gently lifting the presenting part and continuously holding it off the prolapsed cord to restore fetal blood flow while immediate cesarean delivery is done. Placing the woman in the knee-to-chest position and giving her terbutaline 0.25 mg IV once may help by reducing contractions.