Umbilical cord abnormalities

By (embryologist) and (fertility counselor).
Last Update: 05/04/2016

The umbilical cord is a flexible structure that acts as a link between the mother and the baby. Its role during pregnancy is to provide the baby with all necessary nutrients, and eliminate the baby's waste products.

Throughout pregnancy and during delivery, a number of complications related to the umbilical cord may arise. From false umbilical cord knots—which do not pose a problem either for the woman or the baby—to vasa previa. The latter, however, can even lead to fetal death.

Thanks to the latest advances in prenatal ultrasonography, many of these complications can be diagnosed when the fetus is still in the uterus, although there are some that can only be detected just before childbirth.

Among the different alterations of the umbilical cord that can damage both the fetus and the mother, we highlight the following:

  • Abnormal umbilical cord coiling, usually around the fetal neck.
  • Single umbilical artery (SUA). The umbilical cord has normally two arteries and one vein; this pathology when it lacks one of these arteries.
  • Cord knots
  • Vasa previa: fetal blood vessels run near the internal orifice of the uterus instead of the fetus.

In addition to the above listed, umbilical cord prolapse is another complication, which shall be explained hereunder.

Umbilical cord prolapse (UCP)

Umbilical cord prolapse is a complication that occurs when the cord comes out of the birth canal prior to the fetus, thereby causing the compression of the umbilical cord on the fetal head—less frequently it may also occur in the buttocks. This translates into a limitation in the blood flow and amount of oxygen that reaches the fetus, which in turn could cause a diminished fetal heart rate, and put the baby's life at stake.

In most cases, this alteration could be normalized by supplying the pregnant woman with oxygen and fluids, although sometimes inducing labor naturally becomes necessary through vacuum or forceps, or even performing a C-section.

Nonetheless, this complication appears usually in around 1 out of every 300 childbirths.

What causes UCP?

The most common cause behind UCP is the premature rupture of the membranes containing amniotic fluid. Other possible causes are:

  • Artificial rupture of the membranes (amniotic sac) during labor induction.
  • Low lying placenta

Diagnosis and treatment

Umbilical cord prolapse can be diagnosed by means of the following procedures:

  • Prenatal observation of umbilical cord, whether it is directly located on the vulva or through a speculum in the vagina.
  • By touching the cord through vaginal examination.
  • Reduced fetal movements
  • Changes in appearance of amniotic fluid

This alteration can pose an increased risk due to a lack of oxygen in the fetus—therefore, it should be treated as soon as possible. The treatment will involve any method that helps reduce the pressure exerted by the cord on the fetus and improve fetal circulation.

Decreasing uterine dynamics, filling the maternal bladder with a saline solution, placing the patient in a knee-chest position, or administering oxygen to the mother are some of the most recommended actions.

Only in cases where natural childbirth may be imminent without posing a trauma, it will be carried out vaginally. However, in most situations, especially the most severe ones, labor is induced via C-section, since the later UCP is solved, the greater the chances of vital problems in the baby to arise—e.g. brain damage or death.

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 Andrea Rodrigo
Andrea Rodrigo
B.Sc., M.Sc.
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics. More information about Andrea Rodrigo
Adapted into english by:
 Sandra Fernández
Sandra Fernández
B.A., M.A.
Fertility Counselor
Bachelor of Arts in Translation and Interpreting (English, Spanish, Catalan, German) from the University of Valencia (UV) and Heriot-Watt University, Riccarton Campus (Edinburgh, UK). Postgraduate Course in Legal Translation from the University of Valencia. Specialist in Medical Translation, with several years of experience in the field of Assisted Reproduction. More information about Sandra Fernández

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