Gross patterns of umbilical cord coiling: correlations with placental histology and stillbirth.

INTRODUCTION: The purpose of this study was to define gross patterns of umbilical cord hypercoiling and determine correlations with histological features in the placenta and/or perinatal outcomes such as stillbirth.
METHODS: Gross images of placentas with hypercoiled umbilical cords (>3 coils/10 cm) were assigned a major umbilical coiling pattern and the direction (right or left) of the coiling. Definitions of 4 gross coiling patterns were established: undulating, rope, segmented, and linked, each with progressively deeper indentations in cord diameter. Outcome variables obtained from placental pathology reports and maternal medical records included histological abnormalities indicative of significant chronic fetal vascular obstruction, such as fetal vascular thrombi, avascular villi, villous stromal-vascular karyorrhexis, and fetal thrombotic vasculopathy, and stillbirth.
RESULTS: 318 placentas/umbilical cords met inclusion criteria. The rope pattern was the most common (52%), followed by the undulating (26%), segmented (19%) and linked (3%) patterns. The segmented and linked gross coiling patterns were significantly correlated with histologic evidence of chronic fetal vascular obstruction and stillbirth, when compared with the ropeand undulating patterns. Cords with right twists were also significantly correlated with histologic evidence of chronic fetal vascular obstruction and stillbirth when compared with cords with left twists. The number of cord coils per 10 cm did not correlate with any of the outcome variables.
CONCLUSIONS: Among hypercoiled umbilical cords, specific gross patterns of coiling can be recognized, and patterns with the most significant indentation or pinching of the cord diameter are associated with histological evidence of chronic fetal vascular obstruction and stillbirth.