Umbilical cord entanglement around the neck is a common occurrence during pregnancy. While complications from this condition are rare, there is no need to abandon natural childbirth solely because of this issue.
Of course, since the umbilical cord is located within the uterine cavity, its actual condition cannot be fully assessed externally.Abnormalities such as true umbilical knots, short umbilical cord, or mechanical attachment may exist. Consequently, complications during delivery can sometimes arise due to umbilical cord issues. When such incidents occur, expectant mothers and their families often struggle to accept the outcome, leading to skepticism about medical diagnoses and treatments.The reality is that modern diagnostic techniques cannot precisely describe the umbilical cord's condition during pregnancy. Once situations like excessive cord traction or umbilical vessel rupture occur, irreversible complications often develop within a very short timeframe. However, it remains consistent with medical science and treatment principles to perform cesarean sections for nearly one-quarter of mothers due to these rare events. Of course, with the advancement of science and technology, we believe that one day we will resolve more clinical challenges.
Types of Umbilical Cord Abnormalities
1. Abnormal Cord Length: Normal cord length ranges from 30 to 70 centimeters, averaging 50 to 60 centimeters. A cord shorter than 30 centimeters is termed short cord.Short umbilical cord often presents no clinical symptoms before labor. During labor, as the presenting part descends, the cord becomes excessively taut, obstructing fetal blood circulation and causing fetal hypoxia. Additionally, cord traction may lead to premature placental abruption. A cord exceeding 70 cm is termed an excessively long umbilical cord.An excessively long cord is prone to causing nuchal cord, body entanglement, prolapse, or cord compression.Upon membrane rupture, the cord may further prolapse below the presenting part, descend through the cervix into the vagina, or even protrude from the vulva—a condition termed umbilical cord prolapse. Both umbilical cord presentation and prolapse can cause fetal hypoxia and increase the rate of operative delivery.
3. Umbilical Cord Entanglement: Refers to the cord wrapping around the fetal body, most commonly around the neck.
4. Umbilical cord knots: Includes true and false knots. A false knot occurs when the umbilical vessels, being longer than the cord itself, coil into a knot-like appearance, typically posing no harm. True knots most commonly develop during the third to fourth month of pregnancy, formed when the fetus passes through a loop of the cord. If a true knot tightens, it can obstruct fetal blood circulation, leading to intrauterine fetal death.
5. Umbilical cord torsion: Repeated fetal movements within the uterus can cause the cord to twist around its longitudinal axis. Excessive torsion may cause thinning and necrosis of the fetal umbilical ring, vascular occlusion, and fetal death.Vagrant Umbilical Cord Attachment: Normally, the umbilical cord attaches to the placenta. If it attaches to the amniotic membrane instead, the cord vessels enter the placenta through the space between the amnion and chorion—a condition termed vagrant umbilical cord attachment. In such cases, placental abruption with bleeding can cause fetal death due to blood loss.