The umbilical cord twist: origin, direction, and relevance

Area of Science:

• Obstetrics and Gynecology
• Developmental Biology
• Fetal Medicine

Background:

• The umbilical cord's twist is a common feature at birth.
• The origin and significance of this twist are not fully understood.
• Previous hypotheses suggested a link between cord twist and fetal handedness.

Purpose of the Study:

• To investigate the origin and direction of umbilical cord twists.
• To determine the relevance of cord twist direction to fetal handedness.
• To explore factors influencing cord twist development.

Main Methods:

• Analysis of 2801 singleton placentas to document cord twist characteristics.
• Evaluation of hand preference and performance in 45 children with known cord twists.
• Correlation of cord twist with fetal handedness, maternal handedness, single umbilical artery, intrauterine fetal deaths, and twin gestations.

Main Results:

• A left twist was observed 7 times more frequently than a right twist; 5% of cords lacked twist.
• Cord twist direction was independent of child and maternal handedness.
• Absent or right twists were more common with single umbilical artery.
• Absent twists were more frequent in intrauterine fetal deaths and twins, suggesting reduced fetal movement impacts twisting.

Conclusions:

• The direction of umbilical cord twist is not correlated with fetal handedness.
• Hemodynamic forces within the cord itself may not be the primary driver of twisting.
• Decreased fetal movement appears to impede normal umbilical cord twisting.
• Absence of umbilical cord twist may indicate an adverse fetal prognosis.