RÉSUMÉ
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.