Venous flow through coiled and noncoiled umbilical cords. Effects of external compression, twisting and longitudinal stretching.

OBJECTIVE

To examine the association between umbilical cord coiling and perinatal morbidity.

STUDY DESIGN

Ten umbilical cord segments, six coiled and four noncoiled, were categorized according to Strong's coiling index and were examined experimentally. The umbilical arteries and vein were perfused, pressurized, placed in a saline bath at 37 degrees C and subjected to compression, twisting and stretching while measuring venous flow.

RESULTS

There was no statistically significant difference in umbilical venous flow between coiled and noncoiled cords when external compression, twisting and longitudinal stretching were applied to the cord segments.

CONCLUSION

Differences in morbidity associated with umbilical cord coiling should not be attributed simply to mechanical factors, and other mechanisms should be sought.