Implications of Differences in Coiling Indices at Different Segments of the Umbilical Cord

Abstract

The purpose of this study was to find out if the coiling density is similar in all segments of term singleton umbilical cords. We compared the coiling index (coils/cm) at three different segments of 159 cords. There was no statistical difference between the coiling indices of the placental and middle segment, but significantly increased coiling was found at the fetal end compared with the placental and middle segments. Coiling indices were not significantly correlated with gestational age, cord length or birth weight. We diagnosed concordant hypo- and hypercoiling when the placental and fetal segments had the same density classification, and discordant hypo- and hypercoiling when these segments had different density classifications. Concordant hypocoiling and hypercoiling were found in 4.4 and 6.3% of the cords examined, respectively (total of 10.7%), concordant normal coiling in 95 (59.7%) and discordant density classifications in 29.6%. We concluded that the coiling index should be established in two distinct segments and that the spatial configuration of the coils, which protects the blood flow in the umbilical cord, might not be measured by coil density only.

Is the Sampling Site along the Umbilical Artery Significant?

“…The sampling site of cord blood might cause changes in pH and blood gases because the umbilical cord is not an inert conduit and the blood is not an inactive tissue [4,6,12]. It could be argued that changes are expected downstream the umbilical artery and therefore the sampling site should be standardized in order to accurately measure pH and blood gases.…”

Evidence-based pathology: umbilical cord coiling

“…Edmonds argued that this is 'reasonably standard and may be neglected because of this constancy'. 6 Authors have described lengths of 2 cm, 7 3 cm, 8 5 cm, 9 and 10 cm 10 as being the length the cord is routinely cut from the fetal abdomen. In and of itself, the amount of cord that is discarded from calculating the coiling index may not be important but for the fact that the coiling is greater at the fetal end than at the middle or placental ends of the cord.…”

“…In and of itself, the amount of cord that is discarded from calculating the coiling index may not be important but for the fact that the coiling is greater at the fetal end than at the middle or placental ends of the cord. 8 The cord reportedly shrinks by as much as 7 cm in the first few hours after delivery 11 and the time interval between delivery and measurement is often not mentioned in the studies. Authors described measuring the cord 'immediately after delivery', 12 'shortly after delivery' 13 and within 1 hour.…”

“…Authors described measuring the cord 'immediately after delivery', 12 'shortly after delivery' 13 and within 1 hour. 8,14,15 One group of investigators described examination of the cord by the resident physician or nurse attending the delivery within 2 hours post-partum, and again by the authors within 24 hours after storage at 58C, but it is not clear whether one or two measurements had been made and, if the latter, no comparison between those measurements was provided. 16 Another group had a mixture of measurements made 'after delivery' and 'the following morning' for deliveries that occurred at night.…”

“…8 Notwithstanding the amount of umbilical cord that is attached to the fetal end that is not measured, the effect of inaccuracies of 1 cm, whether due to rounding tendencies or otherwise, is quite substantial. In Table 1, for example, whether a cord with four coils is measured as being 57 cm or 1 cm longer or shorter separates the cord into a normal or hypocoiled cord using the index derived by the Utrecht group.…”