The umbilical cord is vital for the development, wellbeing and survival of the foetus and yet, it is vulnerable to kinking, compressions, traction and torsion, which may affect the perinatal outcome. vessels are the most vulnerable part of the foetal anatomy. The total number of coils for any particular cord is believed to be established early in gestation. The pattern of coiling develops during second and third trimesters, presumably due to snashes in the cord and this coiling changes as pregnancy advances. The three blood vessels pass along the length of the cord in helical or coiled fashions [1]. The helical fusion of these umbilical vessels is termed as spiral course [2].
A coil is defined as having completed a 360 spiral course of umbilical vessel around Wharton’s jelly. Coiling property of umbilical cord was described by Berengarius in1521 [1]. In 1954, umbilical coiling was first quantified by Edmonds who divided the total number of coils by umbilical cord length in centimetres and called it “Index of twist”. He assigned positive and negative scores to clockwise and anticlockwise coiling, respectively [1,3]. Later, Strong et al simplified it by eliminating three directional score and named it “The umbilical cord coiling index” [1,4]. An abnormal umbilical cord coiling index includes both hypocoiled cords (cords with an umbilical cord coiling index which is < 10th percentile) and hypercoiled cords (cords with an umbilical cord coiling index which is > 90th percentile). An abnormal umbilical coiling index has been reported to be related to adverse perinatal outcomes [1,2,5–7].
The present study aimed to evaluate the perinatal outcomes with abnormal umbilical cord coiling indices.
Material and Methods
This was a prospective study which was carried out in the Department of Obstetrics & Gynaecology at Adichunchangiri Institute of Medical Sciences, B.G.Nagara, Mandya, Karnataka, India, from January 2008 to August 2010. Ethical committee clearance was obtained from the Institute’s Research Council and Ethics Committee. 200 patients who were in active labour with term gestations, irrespective of their parities, who had singleton pregnancies with live babies who were either delivered by vaginal or LSCS were included in the study. Patients were observed in second and third stages of labour.
After separating baby from umbilical cord, the cord was tied and cut as close to baby as possible. The umbilical cord was measured in its entireity, including the length of the placental end of the cord and umbilical stump on the baby. Number of complete coils or spirals were counted from neonatal end towards the placental end of cord and it was expressed in cm. After this, UCI was calculated by dividing the total number of coils by the total length of cord in cm.
Then, perinatal factors like meconium staining, foetal weight, Apgar score and ponderal index were correlated with UCI. Thus, the effect of umbilical vascular coiling on perinatal outcome was carried out. All patients and babies were followed till they were discharged.
Results
Among 200 women who were studied, 137 were booked and 63 were unbooked. Primigravida were 129 and multigravida were 71. 110 delivered vaginally, 79 delivered by LSCS, 10 had vaccum deliveries and 1 had an outlet forceps delivery. 90 women who had undergone either LSCS or instrumental deliveries had indications of foetal distress.
In the present study, UCI which was < 10th percentile < 0.06, was considered as hypocoiling whereas UCI which was > 90th percentile > 0.48 was considered as hypercoiling. 156 cords showed normal coiling, 23 showed hypocoiling, and 21 showed hypercoiling. 22 babies weighed < 2.5kg. Meconium staining liquor was present in 42 cases. An Apgar score at 1 min of < 4 was observed in 31 cases and that of > 4 was seen in 169 cases. Apgar score at 5 min was <7 min in 28 cases and it was > 7 min in 172 cases. The twist of the cord was dextral in 77 cases and it was sinistral in 123 cases. 35 babies were admitted to the NICU. 108 were males and 92 were females.
[Table/Fig-1] (in row A,B,C,D) show correlation of meconium staining, Apgar scores at 1 min, Apgar scores at 5 min and NICU admissions with UCI respectively.
Correlation of Meconium Staining, Apgar score, NICU admission, IUGR and Ponderal index with UCI
| Baby details | UCI | P value |
|---|
| Normal | Hypo coiling | Hyper coiling |
|---|
| A. Meconium staining | <0.001 |
| Yes | 17(10.89%) | 23(100%) | 2(9.5%) |
| No | 139(89.11%) | 0(0%) | 19(90.5%) |
| B. Apgar score at 1 min |
| <4 | 23(14.7%) | 7(30.4%) | 1(4.8%) | 0.072 |
| >4 | 133(85.3%) | 16(69.6%) | 20(95.2%) |
| C. Apgar score at 5 min |
| <7 | 19(12.2%) | 7(30.4%) | 2(9.5%) | 0.065 |
| >7 | 137(87.8%) | 16(69.6%) | 19(90.5%) |
| D. NICU admission |
| Yes | 19(12.2%) | 10(43.5%) | 6(28.6%) | <0.001 |
| No | 137(87.8%) | 13(56.5%) | 15(71.4%) |
| E. IUGR |
| Yes | 5(3.2%) | 0(0%) | 17(81%) | <0.001 |
| No | 151(96.8%) | 23(100%) | 4(19%) |
| F. Ponderal index |
| <2.5 | 108(69.2%) | 15(65.2%) | 20(95.2%) | 0.022 |
| >2.5 | 48(30.8%) | 8(34.8%) | 1(4.8%) |
This being statistically significant, it suggests that hypocoiled cords are more associated with meconium staining, low Apgar scores and more NICU admissions of babies. [Table/Fig-1](in row E and F) show correlation of IUGR and ponderal indices with UCI respectively. These are statistically significant, suggesting that hypercoiled cords are associated with IUGR and low ponderal indices.
[Table/Fig-2] shows correlation of UCI with mode of delivery. Hypocoiled cords were significantly associated with incidence of more LSCS.
Correlation of mode of delivery with UCI
| Maternal variables | UCI | p value |
|---|
| Normal | Hypo coiling | Hyper coiling |
|---|
| Mode of delivery | 0.008** |
| FTVD/ FTVMD/ FTVOD | 101(64.7%) | 7(30.4%) | 13(61.9%) |
| LSCS | 55(35.3%) | 16(69.6%) | 8(38.1%) | |
Discussion
Several trials in the past have correlated the relationship between perinatal outcomes and the UCI. In the present study, UCI was compared with various parameters. On comparing UCI with parity, it was found that there was no statistical significance between primigravida and multigravida and that there was no statistical significance between the dextral and sinistral twists of cord. In the present study, hypocoiled cords were significantly associated with LSCS. In the present study, it was observed that meconium staining was significantly associated with UCI which was <10th percentile. Gupta S et al., studied 107 umbilical cords and found that in hypocoiled group, meconium staining was significantly higher than in those with normocoiled group [1]. Strong TH et al., studied 100 cases and they found that meconium staining was associated with UCI values of less than 10th percentile, with a p value of 0.03, which was highly significant [4]. In another study which was done by Padmanabhan LD et al., 130 cases were studied, where they found that meconium staining was significant in hypercoiled group [8].
In the present study, Apgar score at 1 min of < 4 was found with UCI which was < 10th percentile. Gupta S et al., studied 107 umbilical cords and found that in hypocoiled cords, low Apgar scores were present [1]. In another study which was done by Padmanabhan et al., 130 umbilical cords were studied and it was found that in hypocoiled group, there were significantly low Apgar scores [8].
In the present study, Apgar score at 5 min of < 7 in relation to UCI was seen with < 10th percentile. Monique WM et al., studied 885 cases and found that hypocoiling was associated with low Apgar scores [9]. Gupta S et al., studied 107 cords and found that babies with Apgar scores of < 7 had significantly lower UCIs than the babies with Apgar scores of > 7 [1]. Padmanabhan LD et al., studied 130 umbilical cords and found that hypocoiled group was associated with low Apgar scores of < 7 [8].
In the present study, it was observed that IUGR was significantly associated with UCI which was >90th percentile. In a similar study which was done by Monique WM et al., 885 patients were studied and it was found that hypercoiling was associated with small for gestational age infants [9]. Georgiou AM et al., studied 34 cords and it was found that hypercoiled cords were associated with IUGR [10].
In the present study, babies who were admitted to NICU were significantly associated with UCI which was < 10th percentile. Monique WM et al., studied 885 cases and it was concluded that hypocoiling of the cord was associated with NICU admissions of foetal death [8]. Strong TH et al., studied 687 cases and it was found that incidence of foetal death in non coiled group was significantly greater, with a p value of <0.05 [11].
In the present study, cords with UCI which was >90th percentile had low ponderal indices. As ponderal index is low in foetal growth restriction, hypercoiled cords are associated with both foetal growth restriction and low ponderal indices. Gupta S et al., studied 107 cords and it was concluded that there was no statistically significant difference between the hypocoiled group and hypercoiled group in association with ponderal indices [1].
Conclusion
The abnormal umbilical coiling index is associated with adverse perinatal outcomes. UCI which is > 90th percentile is termed as hypercoiling and it is associated with foetal growth restriction. It was found that a ponderal index of < 2.5 was associated with hypercoiling of cord. UCI which is < 10th percentile is termed as hypocoiling and it is associated with meconium staining, low Apgar scores and NICU admissions of babies. Therefore, an antenatal detection of coiling index can identify fetuses who are at risk and thus help in further management.