Umbilical Cord Prolapse
A 23-year-old woman at 38 weeks of gestation is in active labor when spontaneous rupture of membranes occurs. On examination the cervix is 6 cm dilated, the presenting part is high, and a pulsating umbilical cord is felt in the vagina below the presenting part. Which of the following cardiotocographic findings is most expected in this situation?
- A.Recurrent late decelerations with reduced variability
- B.Recurrent early decelerations mirroring contractions
- C.Variable decelerations with fetal bradycardiaCorrect
- D.Frequent accelerations with normal baseline variability
Explanation
Cord prolapse compresses the umbilical cord between the presenting part and the pelvis or cervix, abruptly interrupting umbilical blood flow. Occlusion of the thin-walled umbilical vein first reduces venous return, and subsequent arterial compression triggers a baroreceptor-mediated vagal reflex, producing abrupt decelerations that vary in shape, depth and timing relative to contractions. If compression persists, sustained bradycardia below 110 beats/min develops and signals severe fetal compromise. The classic cardiotocographic signature of cord prolapse is therefore variable decelerations progressing to prolonged bradycardia, often immediately after membrane rupture. Late decelerations, by contrast, arise from uteroplacental insufficiency in conditions such as pre-eclampsia, growth restriction or placental abruption. Early decelerations mirror contractions and reflect benign fetal head compression. Accelerations indicate a well-oxygenated fetus and would not be the expected finding. Management of cord prolapse is an obstetric emergency: elevate the presenting part manually, place the mother in knee-chest or exaggerated Sims position, avoid handling the cord, consider bladder filling, and deliver immediately, usually by cesarean section unless vaginal birth is imminent.
Why each option
- A.
- Late decelerations indicate uteroplacental insufficiency rather than acute cord occlusion, and are typical of pre-eclampsia, growth restriction or abruption.
- B.
- Early decelerations mirror contractions and are caused by benign fetal head compression during descent; they carry no hypoxic significance.
- C.
- Correct. Acute cord compression produces abrupt variable decelerations that progress to sustained bradycardia when occlusion persists.
- D.
- Accelerations reflect a well-oxygenated, non-acidemic fetus and would not be expected once the cord is compressed.
Reference: RCOG Green-top Guideline No. 50, Umbilical Cord Prolapse, 2014, reaffirmed 2022
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