The umbilical cord can be visualized with ultrasound exam by about the 8th week. Second and third trimester ultrasound examination to determine the number of vessels in the cord is recommended by the American Institute of Ultrasound in Medicine, although many experts prefer a more detailed exam of the cord at this time. A detailed evaluation includes assessment of wharton’s jelly (a mucous tissue that protects the umbilical vessels), evaluation of the foetal and placental insertion sites (including location of the cord on the placenta) and determination of the helical pattern (twisting of the cord). There is a relationship between the number of twists and the ratio between length and thickness of cords. The twists begin to be evident during the early part of the 8th week.
Indeed, it is the consensus of researchers that ultrasound studies of the umbilical cord can improve management of the baby. Ultrasounds that view the umbilical cord are performed during the second trimester and sometimes sooner. Length of the cord should be noted, and very close monitoring of the mother and baby must take place if the cord is short or other cord abnormalities are present.
When a short cord is causing the baby to be compromised, the foetal distress will show up on the foetal heart rate monitor as abnormal or non-reassuring heart tracings. This may be recognized when the mother is having prenatal tests performed, such as non-stress tests and biophysical profiles. Also, a short cord may be present along with IUGR and decreased fetal movement. Close monitoring is imperative, and depending on the severity of the condition, it may be necessary to admit the mother for continuous, close monitoring of her and the baby.
Placental abruption is the biggest complication of a short cord because any movement of the baby can pull on the cord’s insertion point on the placenta, causing the placenta to pull away, leading to severe bleeding and hemorrhage. We have seen many cases in which a mother is experiencing placental abruption – with very clear signs – and the medical team fails to appreciate it, causing a delay in delivering the baby. When signs of placental abruption are present, the medical team must put the mother in a position in which her baby can be delivered immediately by C-section, particularly if it is known that the cord is short. Placental abruption can turn severe very quickly, and if the tear is at the cord, the baby must be delivered right away to prevent severe oxygen deprivation and brain damage, such as HIE and cerebral palsy.
Of course, all labor and delivery units should have the capacity to perform a quick C-section when a baby is showing signs of distress. When a cord is too short, there often is a lot of tension placed on the vessels within it during delivery. This shows up as an abnormal or non-reassuring heart tracing, and an emergency C-section must take place right away. The cord can also rupture, which will cause the baby to be cut off from all or most of her oxygen supply.